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Gcd Of Three Numbers In C

If x and y are both even, gcd(x, y) = 2*gcd(x/2, y/2) because 2 is a common divisor. gcd(a, b, c) = gcd(a, gcd(b, c)) = gcd(gcd(a, b), c) = gcd(gcd(a, c), b). Mike wants to change his sequence in order to make it beautiful. Below is a code part that is used to deal with large values. If you’ve the basic knowledge of mathematics, then you would know that we can find LCM very easily using GCD. G = gcd(A,B) returns the greatest common divisors of the elements of A and B. The key idea is that the greatest common divisor of two numbers remains unchanged if you subtract the smaller from the larger. [C++/Java/Python] Greatest Common Divisor. To find the HCF (Highest Common Factor) or GCD (Greatest Common Divisor) of two or more numbers, make prime factors of the numbers and choose the common prime factors. e = 2 => GCD(e, 108. The pseudo code of GCD [recursive] GCD(x, y) Begin if y = 0 then return x; else Call: GCD(y, x%y); endif End. To find the larger of two numbers in PROLOG. Greatest common divisor is also known as greatest common factor (in short: (GCF) and highest common factor (HCF) (in short: HCF). Therefore gcd(a,b) remains same as the gcd of a and b 2. So the greatest common divisor is 5. Using property. C program to calculate GCD of n numbers * use the smallest no to find gcd of n numbers. C PROGRAMMING. Solution Figure 4: Sketches for the resulting signals. hu Abstract We survey properties of the gcd-sum function and of its analogs. Well it's easy. 2, 3, 5, 7, 11, 13, 17, 19, … are primes. A simple web search about GCD in Swift versions other than the last one will give you a good taste of how GCD syntax had been. For k 2Z 8, gcd(8;k) = 1 if and only if k = 1;3;5;7. GCD of two numbers a and b, where (0 <= A <= 40000 and A <= B < 10^250). c < b < a and thus we have made progress by reducing the numbers we have to compute their gcd of. Proof Induction. Below is a recursive C function to evaluate gcd using Euclid’s algorithm. To calculate the GCD, we have to first find the greatest of the three numbers. If p is given as an integer double (type 1), then it is treated as an int32. Look at 125x + 27y = 575 again. Prime Numbers. The proof of our average gcd bound does not use the second main theorem of Nevanlinna theory in any form, but instead, it is based on an elementary construction coming from. each pair of them is relatively pri. The Greatest Common Divisor (GCD) of two whole numbers, also called the Greatest Common Factor (GCF) and the Highest Common Factor (HCF), is the largest whole number that's a divisor (factor) of both of them. Therefore, gcd , =2∙3=6. For instance, the largest number that divides into both 20 and 16 is 4. The greatest common divisor (GCD), also called the greatest common factor, of two numbers is the largest number that divides them both. To count the number of elements in a list in PROLOG. 5 and 20 b. Recursion is the programming technique that a process invoking itself again and again. Euclidean algorithm, procedure for finding the greatest common divisor (GCD) of two numbers, described by the Greek mathematician Euclid in his Elements (c. Again, VS2015 seems to struggle with an ambiguous function call when I use std::accumulate with gcd as. gcd(a, b, c) = gcd(a, gcd(b, c)) = gcd(gcd(a, b), c) = gcd(gcd(a, c), b). Java program to find largest of three numbers using function Java program to find largest of three numbers using function. Beck to Harford, per P. write a shell program for finding out gcd of three given numbers? write a shell program for finding out gcd of three given numbers? write a shell program for finding out gcd of three given numbers. The C program for GCD has a function called hcf(a, b) which is called recursively until remainder is 0. An urn contains 75 white balls and 150 black balls. Hence kc = dc, i. Write a C, C++ program to find smallest of three numbers. In a recursive algorithm, the computer "remembers" every previous state of the problem. Therefore LCM of two numbers is given by: LCM = (n1 * n2) / HCF We know that, HCF (highest common factor) = GCD (greatest common divisor) So, LCM = (n1 * n2) / GCD. Pick any 4 positive integers. At this step we claim that the previous (the last non-zero) remainder is exactly the greatest common divisor of the two original numbers. The GCF is the largest common positive integer that divides all the numbers (3,4,5) without a remainder. Linear Combinations and the Greatest Common Divisor (a) Determine the greatest common divisor of 20 and 12? (b) Let $$d = \text{gcd}(20, 12)$$. The key idea is that the greatest common divisor of two numbers remains unchanged if you subtract the smaller from the larger. 300 BC describes an efficient algorithm for calculating the greatest common divisor. If x and y are both even, gcd(x, y) = 2*gcd(x/2, y/2) because 2 is a common divisor. The gcdof and can only have as many of each prime factor as the two numbers have in common. (ii) for every other common divisor c it hold that c|d. c² - d² , c (c - d) Solution. (a) With the notation from the discussion of the gcd in text, show that for each i, there is an invertible 2-by-2 matrix Q i with integer entries, such that Q−1 i also. '-'for subtraction. Question: Write a Program in Java to input 2 numbers and find their Greatest Common Divisor (GCD). The GCF is also known as: Greatest common divisor (gcd); Highest common factor (hcf);. Note: Negative numbers are also included, as multiplying two negatives makes a. (2) Proving that Carmichael numbers are squarefree. Also Read: Python GCD – 4 Ways to Find GCD or HCF. Sample Input 1. Adding two evens or adding two odds results in an even number. Example: Two bands are to be combined to march in a parade. If it does, this is our GCD, otherwise we continue on checking numbers less than the minimum. Let's Code : [code]#include int main() { int a,b,c,hcf,st; printf("Enter three numbers : "); scanf("%d,%d,%d", &a,&b,&c); st=a #include void main() { int a,b,c,l,g,p,i; clrscr(); printf. GCD of two numbers a and b, where (0 <= A <= 40000 and A <= B < 10^250). 315 = 3 2 x 5 x 7. Inside the loop, we are checking if the number n is divisible by the current loop variable (i) i. C++17 - find the greatest common divisor, gcd, of two or more integers Posted on October 25, 2019 by Paul. F) or greatest common divisor (G. gcd(2,6) = 2 > 1 and gcd(6,3) = 3 > 1, so (2,6),(6,3) ∈ R. "In mathematics, the Euclidean algorithm, or Euclid's algorithm, is a method for computing the greatest common divisor (GCD) of two (usually positive) integers, also known as the greatest common factor (GCF) or highest common factor (HCF). Note that gcd(a,b) = 3 6= 1. Based on this rule it is calculated the greatest common factor, GCF, (or greatest common divisor GCD, HCF) of several numbers, as shown in the example below: 1,260 = 2 2 × 3 2 3,024 = 2 4 × 3 2 × 7. Write a C, C++ program to find smallest of three numbers. The greatest common divisor of an array p of real numbersof real numbers can be obtained by converting it to a polynomial before calling gcd, through p = inv_coeff (p, 0). C program to find HCF and LCM: The code below find the highest common factor and the least common multiple of two integers. M = (x * y) / G. If one of the given squares is odd and one even, let a and c denote odd numbers with 1. D Must Read: Find LCM of Two Numbers in C Programming Note: This C Program To Check LCM of more than 2 Numbers is compiled with GNU GCC Compiler and written in gEdit Editor in Linux Ubuntu Operating System. (a) Show that a given nonsquarefree number n can be written in the form n = pℓN for some prime p and integers N and ℓ with ℓ ≥ 2 and gcd(p,N. If you’ve the basic knowledge of mathematics, then you would know that we can find LCM very easily using GCD. of any polynomial we would also follow this procedure. Let’s Code : [code]#include int main() { int a,b,c,hcf,st; printf("Enter three numbers : "); scanf("%d,%d,%d";, &a,&b,&c. The Cherno Recommended for you. Greatest Common Divisor (GCD) The GCD of two or more integers is the largest integer that divides each of the integers such that their remainder is zero. This java program is similar to above program except that here we are using a user defined recursive function "getGcd" which takes two integers are input parameters and return the gcd of two numbers. If gcd(a,b) = 1, then we say that a and b are relatively prime. For example, =GCD(60,36) returns 12. Label them so that z is the smallest. This is easily expanded to include any number of integers: gcd(27,30,36,81)=3. Thus in our example gcd(a;b) = au+ bvwhere u= 5 and v= 7. Use common test data files to test the algorithm where practically possible. c++ program of gcd of three number?. This algorithm does not require factorizing numbers, and is fast. Therefore the greatest common divisor will be 2 times the gcd of numbers a 2 and b 2. The GCF is also known as: Greatest common divisor (gcd); Highest common factor (hcf);. Thus we discover the more known algorithm of GCD through successive Euclidean divisions, by improving the present algorithm of subtractions. 2 and 3 are the prime number common to all given numbers. 3 6 1 47 A Survey of Gcd-Sum Functions L´aszl´o T´oth Department of Mathematics University of P´ecs Ifju´s´ag u. For example, the gcd(2,4) = 2 and gcd(5,7)=1. We will call this mutually coprime, coprime in pairs, or an analogous term. Constraints. GCD of two numbers using recursion in c++ Posted on April 10, 2015 by Dev Posted in C++ | Tagged GCD , Greatest common divisor , greatest common factor | Leave a comment. If one input argument is nonscalar, then gcd expands the scalar into a vector or matrix of the same size as the nonscalar argument, with all elements equal to. Since c is smaller in absolute value than b, we will reach c =0 after finitely many steps. What I am trying to do is take three numbers and find if each pair is relatively prime (where the GCD is one). cout<<"The GCD of the 3 numbers is: "<, the behavior is undefined. The first few Fibonacci numbers are 0,1,1,2,3,5,8. Output Format: The first line contains the HCF of these N numbers. Prove that the three numbers st; s2 t2 2; and s2 + t2 2 are pairwise relatively prime (i. lcm  6 , − 8 , 3 , 4 , 12. Bitwise Right Shift Operator in C It is denoted by >> Bit Pattern of the data can be shifted by specified number of Positions to Right When Data is Shifted Right , […]. Otherwise, continue to the next step. (3) Suppose gcd(m,n) = gcd(a,m) = gcd(a,n) = 1. gcd(18,24) = 6. 27 + 125 = 152, so 125(x-3) + 27(y-3) = 575 - 3*152 = 119 remembering xcorr = 3, ycorr = 3 we solve 125x+ 27y = 119. (ii) Let k ≥ 2 and assume 2,3,4,,k are each a product of primes. This is because in order for a sum to be odd, one of the numbers must be even and the only even prime number is 2. The __GCD calculator__ computes the greatest common divisor of two or more integers. Write a C program to find greatest common divisor GCD of the given three number The greatest common divisor is the largest number that can divide into all the members of a given set evenly. data no1 dw 0120 no2 dw 0090 gcd dw 0h. Use the Euclidean Algorithm to find $(34709,100313). GCD of two numbers is the largest positive number that divides both numbers without remainder. Example: GCD of 20 and 8 is 4. In mathematics GCD or Greatest Common Divisor of two or more integers is the largest positive integer that divides both the number without leaving any remainder. We will proceed in stages. Stack Exchange network consists of 177 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. And this division will give remainder 10. The program must print the GCD (HCF) of these N integers. Definition 2. If gcd(a,b) = 1, then we say that a and b are relatively prime. 12 =GCD(7, 1) Greatest common divisor of 7 and 1. Deﬁnition 4. a) Design three algorithmic level models of an algorithm that finds the Greatest Common Divisor (GCD) of two numbers in the software programming language, C, and the two hardware description languages, VHDL and Verilog. We actually prove much stronger average bounds of which the previous theorem is a special case, see Section 5. Greatest common divisors can in principle be computed by determining the prime factorizations of the two numbers and comparing factors, as in the following example: to compute gcd(18,84), we find the prime factorizations 18 = 2·32 and 84 = 22·3·7 and notice that the "overlap" of the two expressions is 2·3; so gcd(18,84) = 6. Step1: Express the numbers as product of. The code does not account for negative numbers, yet the number type (int) allows them. Download our mobile app and learn how to find GCF of upto four numbers in your own time: Android and iPhone/ iPad Related Find hcf of: 20 & 30 30 & 45 50 & 75 2 & 3 70 & 105 20 & 15 10 & 30 30 & 15 10 & 45 50 & 15 10 & 75 70 & 15 10 & 105. Suppose you want to find GCD of two numbers – a and b. If one of the integers is 24, what is the smallest possible value of the other one?. Use the Euclidean Algorithm to find the greatest common divisor$(105,300)$and then write this as a linear combination of these integers. How to Find the Greatest Common Divisor by Using the Euclidian Algorithm - Duration: 4:10. (c) Generate at least six different linear combinations of 20 and 12. In this question, We take three input numbers from a user and print the smallest of three numbers. Greatest Common Divisor and Least Common Multiple. Related Read: while loop in C programming. Find more on Program to find greatest number from one dimensional array Or get search suggestion and latest updates. If a\mathrel{∣}b and c\mathrel{∣}b, then it may be true that ac\mathrel{∣}b. find max(x, y) and save to variable ‘a‘. Here GCD stands for Greatest common divisor. Consider a collection of all such products for various choices of the initial four numbers. Let h be the greatest common divisor of x, y, z. [C++/Java/Python] Greatest Common Divisor. 540 = 2 × 2 × 3 × 3 × 3 × 5 = 2 2 × 3 3 × 5. Greatest Common Divisor(GCD) or Highest Common factor ( HCF ) : The greatest number that exactly divides all the given number is the GCD or HCF of those numbers. In the previous chapter we have learnt about Bitwise Left Shift Operator. As new results, we establish asymptotic formulae with remainder terms for the quadratic moment and. Once we get the GCD, we use the below formula to calculate LCM. LCM of speci c numbers. The Euclidean algorithm is one of the oldest algorithms in common use. C Program to find the GCD and LCM. Example = 2 Find the GCD of 20, 30,& 40 by Successive Division Method ? Answer = As here three numbers are given, so it involves Two Phases. Problem Set 3 Solutions Due: Tuesday, February 22 at 9 PM Problem 1. Thus, the greatest common divisor of a and b is the same as the greatest common divisor of b and c. Addition of two natural numbers Exercises. The GCD of two positive integers is the largest integer that divides both of them without leaving a remainder (the GCD of two integers in general is. Explanation of FUNCTION: A function is a block of code that has a name and it has a property that it is reusable i. TIP: The basic formula behind the Least Common Multiple or LCM in C is: LCM(a, b) = (a * b) / GCD. Stack Exchange network consists of 177 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Thus, the GCD in the example is A(n 1;1) = A(4;1) = 9. C020 A C program to find the GCD of given numbers using recursion. The Chinese Remainder Theorem 9 8. HCF (Highest Common factor) or GCD(Greatest Common Divisor): HCF of two or more than numbers is the greatest number (divisor) that divides all the given number exactly. This is certainly true of a and b are powers of different primes. Use the Euclidean Algorithm to find the greatest common divisor$(105,300)$and then write this as a linear combination of these integers. The GCD of two numbers a and b is the greatest number c such that a%c==0 and b%c==0. Below is a code part that is used to deal with large values. The Cherno Recommended for you. com Activity Overview In this activity, students use Venn Diagrams to classify numbers. The elements in G are always nonnegative, and gcd(0,0) returns 0. And this division will give remainder 6. The lcm command will compute the least common multiple of an arbitrary number of polynomials, where the gcd command will compute the greatest common divisor of two polynomials. Euclidean algorithm for computing the greatest common divisor. Chris Raymaakers 208,093 views. The Least Common Multiple. Find the least common multiple of 5. GCD is typically denoted using round brackets - (a,b) denotes the gcd of a and b. (3) Suppose gcd(m,n) = gcd(a,m) = gcd(a,n) = 1. C Program To Find Out Gcd Of Numbers Ad Bot Program - Ad Spy Program - Ad Swap Program - Address Phone Numbers - Adpcm Program - Adrift Program - Adsorb Program Code 1-20 of 60 Pages: Go to 1 2 3 Next >> page. ；或者Greatest Common Divisor，簡寫G. If the numbers a, b have gcd = 1, we see that they share no common factors besides 1. Find the largest common divisor of the products in the collection. The HCF or GCD of two integers is the largest integer that can exactly divide both numbers (without a remainder). Area of triangle= sqrt[s(s-a)(s-b)(s-c)] Where a, b and c are three sides of the triangle and s=a+b+c/2 Using the function write a program to find GCD of 3 integers. It is otherwise called as greatest common factor or greatest common measure. C++ has a standard function max() which returns the maximum of two less-then-comparable objects. of any polynomial we would also follow this procedure. It's popularly used in investment, profit, loss, speed, distance, volume, density, etc. C program to check whether an integer number is power of two (2) or not In this program, we will read an integer number and check whether the number is Power of Two (2) or not. Therefore the above UPC code is valid. Deﬁnition 3 (Greatest common divisor, relatively prime) The greatest common divisor, gcd(a;b), of two integers a and b is the largest of their common divisors, except that gcd(0 ; 0) = 0 by deﬁnition. 15 – 1, 3, 5. This is know as the greatest common divisor (GCD), or the highest common factor (HCF). The greatest common divisor (gcd) of two positive integers is the largest integer that divides both without remainder. Definition 2. Common Divisor : A number which exactly divides all the given numbers is a common divisor of those numbers. Either k +1 is prime or else it can be written k +1 = u. If it does, this is our GCD, otherwise we continue on checking numbers less than the minimum. C Program to find the GCD of Three Numbers In this case we have to find the GCD of three numbers. (11 points) Let a,b,c ∈ Z be positive. The GCD of two numbers a and b is the greatest number c such that a%c==0 and b%c==0. Some are based on the classical Euclidean algorithm and. Beck to Harford, per P. 2lf restricts the number till 2 decimal places. The GCF is also known as: Greatest common divisor (gcd); Highest common factor (hcf);. Related Read: while loop in C programming. Boundary Conditions: 2 <= N <= 100 Example Input/Output 1: Input: 4 15 20 30 50 Output: 5 from. greatest common divisor. I Current implementations for Z[p 2] and Z[p 3] involves bitshifting the components of each number by about half their bitsize and approximating the quotient with these. When one has to add three or more terms in a calculation of a 3-j or a 6-7 symbol, then for each pair of numbers the subroutine finds the common denominator, takes out the GCD of the two numerators, trans- forms what remains of the numerators into integers, adds, and then transforms the sum back to the Rotenberg form. For example, =GCD(60,36) returns 12. The method is computationally efficient and, with minor modifications, is still used by computers. Input Format: The first line contains N. The pseudo code of GCD [recursive] GCD(x, y) Begin if y = 0 then return x; else Call: GCD(y, x%y); endif End. 2 GCD and LCM The greatest common divisor of two positive integers a and b is the great-. This works because GCD(x,y,z) = GCD(GCD(x,y),z). Z 6, Z 8, and Z 20 are cyclic groups generated by 1. The greatest common divisor of two numbers is the largest number that divides evenly into both. And this division will give remainder 10. The GCF is the largest common positive integer that divides all the numbers (3,4,5) without a remainder. C++17 - find the greatest common divisor, gcd, of two or more integers Posted on October 25, 2019 by Paul. The Excel GCD function returns the greatest common divisor of two or more integers. Prove that if GCD(a;c) = 1 and GCD(b;c) = 1, then GCD(ab;c) = 1. But, by this time, you may have ﬁgured out a way to do so. Counts all occurrence of all numbers. This example shows you the way to find (GCD). The gcdof and can only have as many of each prime factor as the two numbers have in common. In programming these are referred to as floating point numbers. Let a = 365 and b = 211. Prove that a and b are both divisible by p. gcd of two numbers in java. Otherwise, continue to the next step. Recursion is the programming technique that a process invoking itself again and again. The concept is easily extended to sets of more than two numbers: the GCD of a set of numbers is the largest number dividing each …. Greatest common divisor In mathematics, the greatest common divisor ( gcd ), also known as the greatest common factor ( gcf ), or highest common factor ( hcf ), of two or more non-zero integers, is the largest positive integer that divides the numbers without a remainder. For each test case write one number - the number of prime numbers Johnny wrote in that test case. 1 Explanation 1. Write C code to solve the Tower of Hanoi problem. (2) Proving that Carmichael numbers are squarefree. Suppose you want to find GCD of two numbers – a and b. Medium #18 4Sum. But using property 3 and 4 mentioned above, we can simplify the calculation of the gcd of two numbers by reducing it to the calculation of the gcd of two smaller numbers. LCM is an abbreviated form for Least Common Multiple. Greatest Common Divisor (GCD) The GCD of two or more integers is the largest integer that divides each of the integers such that their remainder is zero. This way is: Find all divisors for every number you have. But I am not getting how this method works. If [x] and [y] belong to H, then x ≡ 1 (mod 3) and y ≡ 1 (mod 3), so it follows that xy ≡ 1 (mod 3), and therefore [x]· [y] = [xy] belongs to H. Thus we discover the more known algorithm of GCD through successive Euclidean divisions, by improving the present algorithm of subtractions. C program to find lcm and gcd/hcf of two numbers. C Program to find LCM and HCF (GCD) of two numbers Posted by Akash on 04 September 2013 This is a program code to compute LCM (Least Common Multiple) and HCF (Highest Common Factor) of two numbers entered by user in C programming language. \$\begingroup\$As for using std::accumulate, I agree that it's a much simpler way to implement GCD for > 2 integers and I hadn't realized that before. The duplicate primes problem is normally a result of a random number generator with two characteristics. Multiply those factors both numbers have in common. Many ideas in number theory can be interpreted profitably in terms of prime factorizations. The largest integer d such that dja and also djb is called the greatest common divisor of a and b. Proof: By reordering if necessary, we can assume and since, if or , the statement is trivial. I also know that gcd (a+b, c+d) divides a+b and c+d, so it will divide any linear combination of a+b and c+d. * Start checking from small to 1 whether the * same value divides all the given inputs */ for (i = small; i > 0; i--). Write C code to check if an integer is a power of Write a C progam to convert from decimal to any ba Write a C program which produces its own source co Write C code to return a string from a function. For example, X=20= 2*2*5 Y=30=2*3*5 GCF=2*5=10 LEAST COMMON MULTIPLE (LCM). Let , the greatest common divisor of and. Find two numbers whose gcd is 1, for which the Euclidean Algorithm takes 10 steps. The Greatest Common Divisor As a Linear Combination E. 3 6 1 47 A Survey of Gcd-Sum Functions L´aszl´o T´oth Department of Mathematics University of P´ecs Ifju´s´ag u. Write an algorithm an draw the flowchart to compute the average of the three numbers? Write an algorithm and draw the flowchart to find the largest number amoug two numbers? write a c program to swap two numbers; How to write a algorithm? What is mean by Operator Precedence and Associativity in C Language? C Languages Relational Operators. We can find integers and and such that. The same can be also said to show gcd (c,d) = 1, gcd (a,c) = 1, and gcd (b,d) = 1. to measure the quantitative relationship between two or more quantities. C function to find to the factorial of a given integer. Three numbers may be coprime (i. The GCD (Greatest Common Divisor) of two numbers is the largest positive integer number that divides both the numbers without leaving any remainder. Ahmer siddiqui on C++ program to find ASCII Code for Characters and numbers; OG Mally Bieber ᵀᴿᵁᴹᴾ on Android SQLite Database Tutorial (Select, Insert, Update, Delete) Subham Kuamr on C++ Examples – C++ program to find HCF and LCM of two numbers. 4 it is enough to show that H is closed under multiplication. Write C code to solve the Tower of Hanoi problem. Greatest Common Divisor & Least Common Multiple Calculator This easy-to-use Greatest Common Divisor (GCD) and Least Common Multiple (LCM) Calculator quickly and easily computes the GCD and LCM for any given set of numbers and generates an in-depth solution for the purposes of analysis. For example: GCD of 6, 10 is 2 since 2 is the largest positive number that divides both 6 and 10. Since 6 is a perfect multiple of 3, $$\gcd(6,3) = 3$$, and we have found that $$\gcd(33,27) = 3$$. If you want to know more about the greatest common divisor of two numbers, reading this article first may prove helpful. a*b = GCD(a,b) * LCM(a,b) Using this formula we can find GCD and LCM at a time. C++ program to find LCM using GCD. To get an idea about what the GCD really is, let's go through the steps of finding it for 3 and 6. Boundary Conditions: 2 <= N <= 100 Example Input/Output 1: Input: 4 15 20 30 50 Output: 5 from. For strings S and T, The greatest common divisor must be a prefix of each string, so we can try all prefixes. C Program To Find LCM GCD Of Two Numbers. Therefore 3 is the GCD 3 and 6. Greatest Common Divisor (GCD) The GCD of two or more integers is the largest integer that divides each of the integers such that their remainder is zero. Using Euclid's GCD algorithm to make a continued fraction One of the often studied algorithms in computing science is Euclid's Algorithm for finding the greatest common divisor (gcd) of two numbers. The numbers that these two lists share in common are the common divisors (factors) of 54 and 24: 1, 2, 3, 6. But there is an obvious divisor that stands out! But there is an obvious divisor that stands out! Since both numbers end with zero, they should be divisible by 10. As we know the number will be greater than both of the numbers that why we’re start checking lcm from greater number. C++ has a standard function max() which returns the maximum of two less-then-comparable objects. Adding two evens or adding two odds results in an even number. lcm(c, d) = cd. The greatest common divisor of numbers is a number, which divides all numbers given and is maximal. The gcd cannot be applied to 0. Fermat’s and Euler’s Theorems 10 9. Take two integers you want to find the GCD of; Subtract the two numbers in such a way to get a positive third number; Note the two smallest numbers of the three numbers. The greatest common divisor of the numbers a and b is usually denoted by GCD(a, b) or gcd(a, b). Each of the next lines contains a number: the line contains. The algorithm requires O((log2 uv)2) worst-case time[citation needed], or in other words time proportional to the square of the number of bits in u and v together. find min(x, y) and save to variable ‘b‘. To find the factorial of given number in PROLOG. To count the number of elements in a list in PROLOG. Greatest common divisors can in principle be computed by determining the prime factorizations of the two numbers and comparing factors, as in the following example: to compute gcd(18,84), we find the prime factorizations 18 = 2·32 and 84 = 22·3·7 and notice that the "overlap" of the two expressions is 2·3; so gcd(18,84) = 6. The function uses the following logic on the given input numbers where a is greater than or equal to b. Input Format: The first line contains N. First we recast the Euclidean algorithm for the gcd of two integers in matrix form. (Note that 22 is not a prime. Notation: Let n be the number of entries in the rst column - including the zero entry. Indeed, d is now a common divisor of m n and n. Which gives us a simple rule: if one of the numbers is zero, the greatest common divisor is the other number. Since c is smaller in absolute value than b, we will reach c =0 after finitely many steps. Label them so that z is the smallest. e = 2 => GCD(e, 108. The numbers that these two lists share in common are the common divisors (factors) of 54 and 24: 1, 2, 3, 6. This C program is to find LCM and GCD/HCF of two numbers. Use the Euclidean Algorithm to find the multiplicative inverse for 91 modulo 191. Either k +1 is prime or else it can be written k +1 = u. Example: GCD of 20 and 8 is 4. Therefore LCM of two numbers is given by: LCM = (n1 * n2) / HCF We know that, HCF (highest common factor) = GCD (greatest common divisor) So, LCM = (n1 * n2) / GCD. To count the number of elements in a list in PROLOG. The second step is to analyze which are the common divisors. Therefore 3 is the GCD 3 and 6. (ii) for every other common divisor c it hold that c|d. If you’ve the basic knowledge of mathematics, then you would know that we can find LCM very easily using GCD. For example,GCD of two numbers 8 and 12 is 4. Divide 51 by 17: 51 = 3 17 + 0 STOP! CONCLUSION: gcd(10319;2312) = 17 (the last non-zero remainder). The elements in G are always nonnegative, and gcd(0,0) returns 0. Below is a code part that is used to deal with large values. On the other hand, the primes 5 and 11 cannot be written in this form. Linear Combinations and the Greatest Common Divisor (a) Determine the greatest common divisor of 20 and 12? (b) Let $$d = \text{gcd}(20, 12)$$. p1 and p1 p2 3 g. GCD of two numbers is the largest positive number that divides both numbers without remainder. The algorithm uses the fact that, if A >= B, then GCD(A, B) = GCD(B, A mod B). It also shows a step-by-step solution. An urn contains 75 white balls and 150 black balls. Example : By using Successive Division Method, find the GCD of 24 & 18 ? Answer : Steps and the way of finding GCD by Successive Division Method is as :-Step 1 = Divide the larger number 24 by the smaller number 18. To nd GCD(a;b) write out in list notation the set of divisors of a and the set of divisors of b. And this division will give remainder 6. after that subtract A from C, incrementing xcorr, then subtract B from C, and finally subtract (A-B) from C while incrementing xcorr, decrementing ycorr. Dry run of the program has been given here (click on the link) only additional part is the use of function. GCD of two numbers a and b, where (0 <= A <= 40000 and A <= B < 10^250). Let p be a prime of the form 3k + 2 that divides a2 + ab + b2 for some integers a and b. The Greatest Common Divisor (GCD) of two whole numbers, also called the Greatest Common Factor (GCF) and the Highest Common Factor (HCF), is the largest whole number that's a divisor (factor) of both of them. Therefore the greatest common divisor will be 2 times the gcd of numbers a 2 and b 2. The Greatest Common Divisor As a Linear Combination E. So, GCD(10,12) = 2. Greatest Common Divisor (GCD) The GCD of two or more integers is the largest integer that divides each of the integers such that their remainder is zero. Example- GCD of 20, 30 = 10(10 is the largest number which divides 20 and 30 with remainder as 0) GCD of 42, 120, 285 = 3(3 is the largest number. Following are the steps in finding the GCD of 21 and 333: 333 = 21 x m + 18 21 = 18 x 1 + 3 n = 3 x 6 + 0 The integers m and n are: Select one: a m = 15, n = - Math - Real Numbers. You are probably familiar with ﬁnding greatest common divisors using fac-toring into powers of primes and the Fundamental Theorem of Arithmetic. The full form of GCD is " Greatest Common Divisor". This way is: Find all divisors for every number you have. But I am not getting how this method works. Learn to write a program to find the gcd or HCF and LCM of given two numbers in C++ using for loop. For example, 2 1 is prime for p= 2, 3, 5, and 7, but 211 1 = 2047 = 2389, which is not prime. [] Exceptions. The following C function finds the greatest common divisor of a set of integers using the Divide et Impera method and returns it. It is also known by the name HCF(Highest common factor). Example Input: 2 10 10 100 100 Output: 30 2791. Show that the fraction 12n+ 1 30n+ 2. Given integers aand b (1) The greatest common divisor of a and b, denoted GCD (a;b), is the. For numbers that are small, the binary GCD algorithm is sufficient. 4 thoughts on " C/C++ Program to Find GCD of Two Numbers Using Recursion " junaid kundi March 10, 2016. Write a program in C to find. Below is a code part that is used to deal with large values. It was first published in Book VII of Euclid's Elements sometime around 300 BC. C program to find HCF and LCM: The code below find the highest common factor and the least common multiple of two integers. = 1 and since their subtraction would be p-1 until the number p + (p-1) they would still have g. The key idea is that the greatest common divisor of two numbers remains unchanged if you subtract the smaller from the larger. The full form of GCD is " Greatest Common Divisor". This algorithm does not require factorizing numbers, and is fast. Finding Greatest Common Divisor of 2 numbers in C++. For example, the gcd(2,4) = 2 and gcd(5,7)=1. To find the larger of two numbers in PROLOG. (d) R is the relation on the set of positive real numbers given by xRy if and only. Also Read: Python GCD - 4 Ways to Find GCD or HCF. Using Euclid's GCD algorithm to make a continued fraction One of the often studied algorithms in computing science is Euclid's Algorithm for finding the greatest common divisor (gcd) of two numbers. lcm  6 , − 8 , 3 , 4 , 12. HCF (Highest Common factor) or GCD(Greatest Common Divisor): HCF of two or more than numbers is the greatest number (divisor) that divides all the given number exactly. cout<<"the gcd for the 3 numbers is " < Therefore, gcd(287,91) = gcd(91,14) = gcd(14,7) = 7. If gcd(a,b)=1 and if x₀,y₀ is a particular solution of the linear Diophantine equation ax+by=c, then all solutions are given by x=x₀+bt and y=y₀-at for integral values of t. C Program to Find LCM Using GCD. 2 The Greatest Common Divisor ¶ It seems intuitive that of all the numbers dividing a number (the divisors of the number), one is biggest. To find the HCF (Highest Common Factor) or GCD (Greatest Common Divisor) of two or more numbers, make prime factors of the numbers and choose the common prime factors. Are these linear combinations of 20 and 12 multiples of gcd(20, 12)?. The last remainder of the operations above, not zero, is equal to 1, so GCF (87, 41) = 1 => the numbers are coprime. if n % i == 0 then we print the value of i but if the number n is not divisible by the current loop variable then the loop will continue with other values until the loop is terminated. But I am not getting how this method works. Recall too that a Carmichael number is a composite number n with the property that for every integer a coprime to n we have an−1 ≡ 1 (mod n). I also know that gcd (a+b, c+d) divides a+b and c+d, so it will divide any linear combination of a+b and c+d. C Program To Find Out Gcd Of Numbers Ad Bot Program - Ad Spy Program - Ad Swap Program - Address Phone Numbers - Adpcm Program - Adrift Program - Adsorb Program Code 1-20 of 60 Pages: Go to 1 2 3 Next >> page. If you've the basic knowledge of mathematics, then you would know that we can find LCM very easily using GCD. "In mathematics, the Euclidean algorithm, or Euclid's algorithm, is a method for computing the greatest common divisor (GCD) of two (usually positive) integers, also known as the greatest common factor (GCF) or highest common factor (HCF). Originally Posted by flp1969 This is essentially the same routine I posted before, except you check for divisors by 3 in the beginning (starting the c greatest common divisor is a prime number (pairs of numbers problem in C) - Page 3. However, kc is the least common multiple and dc is a common multiple, so kc ≤ dc. Let Q be the group of rational numbers under addition and let Q be the group of nonzero rational numbers under multiplication. a(n) is the number of ways to express all fractions f/g whereby each product (f/g)*n is a natural number between 1 and n (using fractions of the form f/g with 1 <= f,g <= n). Common Divisors. Click here to learn program on gcd of two numbers in java. SMART POINTERS in C++ (std::unique_ptr, std::shared_ptr, std::weak_ptr) - Duration: 11:37. For example, X=20= 2*2*5 Y=30=2*3*5 GCF=2*5=10 LEAST COMMON MULTIPLE (LCM). That is, $$n$$ is a composite number if there is some integer $$a$$ with $$1= b, the ! Euclid method goes as follows: (1) dividing a by b yields ! a reminder c; (2) if c is zero, b is the GCD; (3) if c is ! no zero, b becomes a and c becomes c and go back to ! Step (1). The C program for GCD has a function called hcf(a, b) which is called recursively until remainder is 0. Inside the loop, we are checking if the number n is divisible by the current loop variable (i) i. Four Numbers, Six Differences, GCD of the Products. LCM of speci c numbers. I think it makes sense to keep the iterator-based gcd() just to have it check for valid inputs and call std::accumulate internally. Then "2" – divisor and "5" – divisor, but only "2 × 5" is Greatest Common Divisor for 10 and 20. Since c is smaller in absolute value than b, we will reach c =0 after finitely many steps. The code for calculating the LCM and GCD is given in the below link. The Cherno Recommended for you. Well it’s easy. C program to check whether an integer number is power of two (2) or not In this program, we will read an integer number and check whether the number is Power of Two (2) or not. The second step is to analyze which are the common divisors. hu Abstract We survey properties of the gcd-sum function and of its analogs. In this article, I will show you how to find the gcd - greatest common divisor of two or more integers with C++, by using two implementations of the classical Euclid algorithm. 4 it is enough to show that H is closed under multiplication. 2, 3, 5, 7, 11 and 13 are few prime numbers. Prime Number Check Program in C. GCD of two numbers is the largest positive number that divides both numbers without remainder. Find the highest common factor for the set of integers using this online Greatest Common Divisor calculator. 11, and 4 3. To create relations in PROLOG; To find the largest of three numbers in PROLOG. 15 - 1, 3, 5. (a) If 2n+ 1 is prime for some integer n, show that nis a power of 2. The lcm command will compute the least common multiple of an arbitrary number of polynomials, where the gcd command will compute the greatest common divisor of two polynomials. (c) Generate at least six different linear combinations of 20 and 12. Use common test data files to test the algorithm where practically possible. It is easy to see that every common divisor of aand bis a common divisor of band c, and con-versely. Solution: (a) The integer m divides n if there exists an integer r such. data no1 dw 0120 no2 dw 0090 gcd dw 0h. = p To find the g. Thereafter, we find the common number that when divided by each of the three numbers gives a remainder 0. You can notice 3 and 5 have no common factor, hence their GCD is 1. The Cherno Recommended for you. However, kc is the least common multiple and dc is a common multiple, so kc ≤ dc. Therefore 3 is the GCD 3 and 6. i have compare data contained in rendered ssrs report (chart , tablix values example) variables stored in c# application. Here's a nice explanation of greatest common factor (or greatest common divisor) along with a few practice example exercises. C Program To Find LCM GCD Of Two Numbers. ；或者Greatest Common Divisor，簡寫G. This syntax supports inputs of any numeric type. To find the GCD of two numbers in PROLOG. Definitions 1. (c) gcd(244, 354) (d) gcd(128, 423). Several numerical methods have been proposed for the derivation of polynomial GCD [1–5]. It is easy to see that every common divisor of aand bis a common divisor of band c, and con-versely. Let’s see the program of “Greatest Common Factor by using Arrays in C++”. Use the Theorem stating GCD(a;c) = ua + vc for some u;v 2Z to conclude that there exists u;v 2Z such that 1 = ua+ vc =) b = bua+ bvc = (ba)a+ (bv)c and so anything the divides both (ba) and c will divide b. State the names of all 14 definitions / propositions from the GCD & Divisors unit -Divisibility-TD: Transitivity of Divisibility-DIC: Divisibility of Integer Combinations-BBD: Bounds By Divisibility-DA: Division Algorithm-GCD: Greatest Common Divisor-GCD WR: Greatest Common Divisor With Remainder-EEA: Extended Euclidean Algorithm-GCD CT: Greatest Common Divisor Characterization Theorem-GCD OO. LCM of speci c numbers. a) 2 533 5 b) 211 39 5 7 11 13 1714 c) 1717 d) 22 53 7 13 e) unde ned (0 is not a positive integer) f) 2 3 5 7 4-3-30 We know that the product of the greatest common divisor and the least common. 10 The Euclidean algorithm works so well that it is difficult to find pairs of numbers that make it take a long time. Our results have applications analogous to some classical number-theoretical problems (see Section 5. In Q, list the elements in h1 2 i. Also Read: Python GCD – 4 Ways to Find GCD or HCF. Linear Combinations and the Greatest Common Divisor (a) Determine the greatest common divisor of 20 and 12? (b) Let \(d = \text{gcd}(20, 12)$$. OPTION 3: APPROXIMATE DIVISION I Calcuation of the quotient limits the Euclidean algorithm’s runtime. Divide 210 by 45, and get the result 4 with remainder 30, so 210=4·45+30. Most of you would have learned about Greatest Common Divisor in middle school itself. Divide 51 by 17: 51 = 3 17 + 0 STOP! CONCLUSION: gcd(10319;2312) = 17 (the last non-zero remainder). Example: 17 and 22. Multiply those factors both numbers have in common. Consider a collection of all such products for various choices of the initial four numbers. The second line contains N integers each separated by a space. 3 Greatest Common Divisor and Least Common Multiple Greatest Common Divisor The greatest common divisor (GCD) of two natural numbers a and b is the greatest natural number that divides both a and b. SMART POINTERS in C++ (std::unique_ptr, std::shared_ptr, std::weak_ptr) - Duration: 11:37. Euclid's Elements c. Find the gcd and lcm of each of the following pairs of numbers: (a) 13, 39 gcd(13,39) = 13, lcm(13,39) = 39 (b) 24, 16 gcd(24,16) = 8, lcm(24,16) = 48 (c) 180, 50 gcd(180,50) = 30, lcm(180,50) = 900 (d) 2 25 37 11 ;2 52 11 gcd = 2 35 211, lcm = 2 5 7 112 6. GCD (HCF) of N Integers N integers are passed as input to the program. 300 BC describes an efficient algorithm for calculating the greatest common divisor. Write an algorithm an draw the flowchart to compute the average of the three numbers? Write an algorithm and draw the flowchart to find the largest number amoug two numbers? write a c program to swap two numbers; How to write a algorithm? What is mean by Operator Precedence and Associativity in C Language? C Languages Relational Operators. Greatest common divisor (in short: GCD) is the largest positive integer that divides two or more numbers without remainder. Each of the next lines contains a number: the line contains. Use the Euclidean Algorithm to find$(34709,100313). The Greatest Common Divisor (GCD) of two whole numbers, also called the Greatest Common Factor (GCF) and the Highest Common Factor (HCF), is the largest whole number that's a divisor (factor) of both of them. c Eli Biham - March 29, 2011 219 Introduction to Number Theory 1. [G,C,D] = gcd(A,B,X) finds the greatest common divisor of A and B, and also returns the Bézout coefficients, C and D, such that G = A*C + B*D. 3 + x 4 + 3x 5 + x 6 + 3x 7 + x 8 + 3x 9 + x 10 + 3x 11 + x 12 then must be divisible by 10. Will the LCM of two numbers ever be greater than their product ? c. Write a C program to find the GCD of two numbers. * Start checking from small to 1 whether the * same value divides all the given inputs */ for (i = small; i > 0; i--). Once we get the GCD, we use the below formula to calculate LCM. 9, License: GPL (>= 3). If gcd(a,b)=1 and if x₀,y₀ is a particular solution of the linear Diophantine equation ax+by=c, then all solutions are given by x=x₀+bt and y=y₀-at for integral values of t. 382 106 Add to List Share. Using Euclid's GCD algorithm to make a continued fraction One of the often studied algorithms in computing science is Euclid's Algorithm for finding the greatest common divisor (gcd) of two numbers. I have also discussed Euclid's algorithm also using recursion. 11, and 4 3. Prove that if GCD(a;c) = 1 and GCD(b;c) = 1, then GCD(ab;c) = 1. The greatest common divisor (archaic: greatest common factor) of two integers a and b is the largest integer that divides them both. Maddison Hughes author of Write a shell program to find the gcd for the 2 given numbers is from London, United Kingdom. Stack Exchange network consists of 177 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. It appears in Euclid's Elements (c. The C program for GCD has a function called hcf(a, b) which is called recursively until remainder is 0. Also, any divisor of 91 and 14 must also be a divisor of 287 = 91 · 3 + 14. Algorithm to find GCD of two numbers using iteration. Output Enter 2 numbers to find GCD 125 85 The GCD of 125 and 85 is 5 Method 2 Another and interesting logic for finding GCD of 2 numbers. The HCF or GCD of two integers is the largest integer that can exactly divide both numbers (without a remainder). proof: Let q be the quotient and r the remainder when a is divided by t. To find the greatest common divisor of rational or complex numbers, convert these numbers to symbolic objects by using sym, and then use gcd. Note that this project uses an iterative method for computing GCD, there is another project Decimal To Rational that uses a recursive. Inside the loop, we are checking if the number n is divisible by the current loop variable (i) i. HCF: Highest Common Factor. As we know the number will be greater than both of the numbers that why we’re start checking lcm from greater number. Examples of Iterative and Recursive Algorithms Greatest Common Divisor (Euclid’s Algorithm) (a 41-digit number) using such a function, the program will. Proposition 2. Are these linear combinations of 20 and 12 multiples of gcd(20, 12)?. Hamerlinck in Alter Ego #169 (May, 2016), added by Craig Delich. Finding Greatest Common Divisor of 2 numbers in C++. The way GCD is used is brand new, totally Swift-like, and the new syntax makes it a lot easier for developers to get familiarised with it. Then the take the highest common factor this highest common factor is HCF of number. M = (x * y) / G. take a prime number and compare them with 1 obviously they will have g. 2 + 6 = 8; 3+5 = 8 Adding an even and an odd results in an odd number. to measure the quantitative relationship between two or more quantities. The numbers can represent the sides of right-angle triangle - call a,b and c the sides of the triple, a and b the legs, c the hypotenuse. 1 =GCD(5, 0) Greatest common divisor of 5 and 0. In mathematics GCD or Greatest Common Divisor of two or more integers is the largest positive integer that divides both the number without leaving any remainder. For example: GCD of 6, 10 is 2 since 2 is the largest positive number that divides both 6 and 10. Greatest Common Divisor(GCD) or Highest Common factor ( HCF ) : The greatest number that exactly divides all the given number is the GCD or HCF of those numbers. We'll use 5 2 since it is the higher degree. The Greatest Common Divisor As a Linear Combination E. Tags for Find GCD of three numbers using recursion in C. Greatest Common Divisor Deﬁnition Let a;b 2Z f 0g. In the below program, we find GCD then the above formula is used to find the LCM. It is also known by the name HCF(Highest common factor). The greatest common divisor (GCD), also called the greatest common factor, of two numbers is the largest number that divides them both. In either case, the GCD is 2kv, where k is the number of common factors of 2 found in step 2. In number theory, Euler's totient function counts the positive integers up to a given integer n that are relatively prime to n. The third property. Either k +1 is prime or else it can be written k +1 = u. cout<<"the gcd for the 3 numbers is " < Therefore, gcd(287,91) = gcd(91,14) = gcd(14,7) = 7. Input Format: The first line contains N. Therefore, gcd , =2∙3=6. Here we'll see how to white a recursive function to find out GCD of two integers, then we'll apply this function for more than two. of any polynomial we would also follow this procedure. Example Input: 2 10 10 100 100 Output: 30 2791. The concept is easily extended to sets of more than two numbers: the GCD of a set of numbers is the largest number dividing each. hi, Can anyone suggest me the approach for finding the lcm of the n numbers? my approach: find the max of the n numbers and start dividing it by all numbers , if all are dividing it then print it, else take next multiple of the max number and repaet the division process. ; Since you provided a complete program you probably want to check whether. Inside the loop, we are checking if the number n is divisible by the current loop variable (i) i. We can carry that idea to two numbers. We will call this mutually coprime, coprime in pairs, or an analogous term. To calculate the GCD, we have to first find the greatest of the three numbers. First, t ≤ 10, the number of test cases. The numbers must be separated by commas, spaces or tabs or may be entered on separate lines. We found that every number is a factor of some Fibonacci number above but it is also true that we can always find a Fibonacci number that begins with a given number as its initial digits. Earlier we found that the Common Factors of 12 and 30 are 1, 2, 3 and 6, and so the Greatest Common Factor is 6. Will the LCM of two numbers ever be greater than their product ? c. (a) If 2n+ 1 is prime for some integer n, show that nis a power of 2. So the greatest common divisor is 5. hi, Can anyone suggest me the approach for finding the lcm of the n numbers? my approach: find the max of the n numbers and start dividing it by all numbers , if all are dividing it then print it, else take next multiple of the max number and repaet the division process. If [x] and [y] belong to H, then x ≡ 1 (mod 3) and y ≡ 1 (mod 3), so it follows that xy ≡ 1 (mod 3), and therefore [x]· [y] = [xy] belongs to H. 1 + 2 = 3 Primes: If the sum of two prime numbers is odd, one of the prime numbers must be 2. Suppose you want to find GCD of two numbers – a and b. I Current implementations for Z[p 2] and Z[p 3] involves bitshifting the components of each number by about half their bitsize and approximating the quotient with these. So, GCD(10,12) = 2. Phase 1 - Find the GCD of 20 & 30 :- Step 1 = Divide the larger number 30 by the smaller number 20. The greatest common divisor is also referred to as _highest common divisor_ or _highest common factor_. model small. For 287 = 91 · 3 + 14. But 2 6= 4. Take two integers you want to find the GCD of; Subtract the two numbers in such a way to get a positive third number; Note the two smallest numbers of the three numbers. (a) With the notation from the discussion of the gcd in text, show that for each i, there is an invertible 2-by-2 matrix Q i with integer entries, such that Q−1 i also. The most common algorithm for finding the greatest common divisor of two numbers is the Euclid's algorithm. This C program is to find lcm and gcd/hcf of two numbers using function. a) Design three algorithmic level models of an algorithm that finds the Greatest Common Divisor (GCD) of two numbers in the software programming language, C, and the two hardware description languages, VHDL and Verilog.
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# Desperate for help!!!!

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circlesoft    1178
Quote:
 Original post by QuadMV 1. Models: Reliable modeling system for animated and non-animated objects. I originally wanted to use .X models, which I’m currently using, but I’m finding that the exporter is terrible, especially for animation. I’d love something like granny, but it’s too expensive.

Have you looked at Cal3D? It is an open-source animation library that has a capable and stable exporter for 3ds Max. I have not used it personally, but have heard of many people who used it with success.

Granny sets the low-end cost-wise of animation middleware, so you aren't going to really find anything less than that (commercially).

Quote:
 2. Shadows: I’ve never done shadows, and need to cast shadows for my models. It’s not trivial but so common it’s mandatory. I'd like something that supports both higher quality, less performance and lower quality higher performance shadows. I'll then choose based on distance.

There are 2 common methods nowadays, each with tons and tons and tons of resources. You can try shadow maps, which basically renders the casted shadows from the viewpoint of lights, or shadow volumes, which basically extrudes geometry. Both have a lot of tutorials on them (both are even in the DXSDK as well).

Quote:
 Instead of getting a formal rendering engine that would limit my abilities to use what I’ve already done, I think maybe what I want are libraries, preferably open source, but I’d even pay if it’s not too expensive. Does anyone know of or possess good quality libraries (source prefered, c++ classes for directX) so I could easily add the missing functionality into my engine? I really want to get to focusing on the game, but I at least need the basic engine to meet minimal standards as defined above.

It seems like the Torque engine is a common solution for indie developers who just want to get up and running fast, but without the cost. Also, OGRE is very nice - it is fully featured and free, too.

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axon    100
DirectX is a graphics API not a game engine. It would take far less of your time to use something which wraps DirectX in some easier to use interfaces.

Try taking a look at:
Ogre3D
Nebula Device

They're both really fantastic game engines which are free. They're also open source so you can see how everything is done and extend it and modify it as you need to.

Also,
Blitz Max

Good luck! And have fun!

Greg

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Thanks guys, but I've thoroughly researched Ogre, irrLicht and Torque as well as others. Although these all have their benefits, none have the features I'm looking for and after evaluating the amount of time it would take to integrate my required feature set into them, I'm believing it'll be less work to add the aforementioned features into my engine and will give me more control and flexibility as I know my engine very well.

I've not looked at Cal3D yet, but I have heard of it. I'll check it out.

Quote:
 There are 2 common methods nowadays, each with tons and tons and tons of resources. You can try shadow maps, which basically renders the casted shadows from the viewpoint of lights, or shadow volumes, which basically extrudes geometry. Both have a lot of tutorials on them (both are even in the DXSDK as well).

Circlesoft, yes I'm aware of the basic concepts. I don't want to do it though. I want to get libraries or classes that will ease the process so I can focus on the more important elements of my engine and more specifically my game.

Expecting there are many experts in these areas already, I'm assuming someone has packaged nice wrappers for these components instead of an entire engine like Ogre or irrLicht or Torque

Quote:
 Granny sets the low-end cost-wise of animation middleware, so you aren't going to really find anything less than that (commercially).

At $12,000 for an indie developer, that's hardly cheap, and even at$1000 for a single development license, I'm just a hobbyist and can't afford that. A $100 is more realistic, and Torque looked very promising at first. It's hard to justify the price of Granny when compared to all the features of Torque for$100. However, after chatting with the Torque developers, the networking is VERY tightly integrated and not meant to be heavily modified without a major impact to the overall architecture. Their networking is designed for multi-user play based on a level approach, not MMOPG based on a persistent (non level) universe.

My engine on the other hand is architected from the ground up for MMOPG in a persistent and non level based universe. It'll support 1000's of planets in a galaxy with 1000's of galaxies, and the player will experience no performance degradation, long loads, delays during transition or anything. It'll all be smooth and natural and instant (near instant anyway).

It's not just the client code either. I've already build most of the middle tier and backend database to run the whole thing.

Quote:
 DirectX is a graphics API not a game engine. It would take far less of your time to use something which wraps DirectX in some easier to use interfaces.

Greg, I appreciate the feedback, but (maybe I'm reading too much into your post and if so I apologize) if you understood my post and checked out my site, I think you'd see that I'm a seasoned DirectX developer and understand the difference between an API and a game engine. The point I was making is that the engine that I'm writing is coming along very well and will stand up to many other engines, but it's lacking some basic functionality like shadows and a particle system.

There are many, many seasoned veterans developing for DirectX and I'd rather buy the functionality to do shadows and particles then spend the time doing it. My focus has been on the less obvious stuff that doesn't exist in other engines like Ogre, Irrlicht or Torque.

Please keep the feedback coming. The more comments and suggestions the better I'll feel that I'm going down the right path.

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Guest Anonymous Poster
DirectX is an engine. It does everything and the d3dx makes stuff like shadows and particles a piece of cake. Shadowmapping is insanely easy i don't understand what the problem is.

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Then maybe you'd like to provide the wrappers for me if it's so easy

;-)

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Guest Anonymous Poster
what wrapper? its just 2 render passes.

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jollyjeffers    1570
To be honest, from what I've seen, what you're referring to (more broadly classed as middleware) rarely comes cheap and/or seperate. You often buy into a particular engine/library and use it for "all or nothing". Pulling out a stand-alone shadowing module (for example) is more difficult than providing a full graphics engine that supports dynamic/generalised shadows as a basic feature...

A couple of possibilities:

1. Bring in another programmer to help things out and get things moving along. If you can't buy in the technology, buy in the talent.

2. You seemed to hint against it, but maybe if you have aspirations as high as you've suggested then putting down your current codebase and using a 3rd party engine/library from scratch is a better plan for the long-run.

[rolleyes] @Anon Poster: I'm sure everyone would appreciate it if you added something useful to the thread. Maybe even used your (obviously far superior) knowledge to help others...

Simple shadow mapping is easy, but getting good, accurate and general shadows at a reasonable speed from SM is definitely not simple. There are lots and lots of special cases in various SM algorithms - trying to get them all balanced so as not to introduce graphical artifacts is no small challenge.

hth
Jack

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Cal3d actually looks very promising. I’m surprised I haven’t heard more about it.

JJ (  can I call you that?). I agree, I was very interested in recent weeks looking at 3rd party engines, but my gaming vision has certain necessary features that just aren’t out there. If I were to give in and use another solution I would have to give up this dream game idea of mine, and I would sooner code it myself ;-). I have also been thinking about porting some of my necessary features to something like Ogre or irrLicht, but I think the learning curve and complexity would be higher than my enhancing my engine. Cal3d looks very promising from a modeling perspective, and I know there are stand-alone particle systems out there. I haven’t mentioned physics yet, but Ogre and irrLicht both rely on 3rd party solutions there, which I could use too. Therefore I’m mostly needing a lighting and shadow solution, which at the end of the day maybe I will implement myself. My terrain is already lit dynamically at runtime with an on the fly generated light map or shadow map (what ever you want to call it). This allows me to let the sun move and have the shading change without reloading everything. I thought a class could be used to simplify shadows, but if not I’ll either bite the bullet and do it, find another to help me, or maybe cal3d helps with this? I’ve not looked into it yet.

Thanks for the input.

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Azh321    569
Im not saying this to bring you down or anything, but do you not have a lot of time to work on your engine? Because it sounds like youve been working on it for years and still dont have the trivial things like decent model support or a good particle system. Jolly has some good points though, maybe bring in another coder.

Good luck to you!

EDIT: BTW I can let you see my particle class, it works pretty good. I will PM it to you when I get home.

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:-) Frankly I don't have nearly enough time. I'm a corporate executive in IT for a large telecommunications company, so I'm lucky I get any time. I'm married with three teenagers, so I have even less time. The time I do get is usually between 12am and 2am. When I was in my twenties that was my prime time of day. In my thirties, I was able to get by. Now that I'm in my forty's it's stressful, but this is still my passion.

Don't misunderstand either, the latest terrain system has only been maybe a 6 month project, and the networking infrastructure another 2 months. This is probably my 5th engine, but this is the one I think meets the level of functionality I need. I took at least a year maybe more off to regroup. I was using DX 1 when it was called the game sdk, and I spent some time in OpenGL before returning to DX.

If I were young, single and didn't have the responsibilities I have it would have been done a long time ago. Actually, until recently, the technology didn't exist to do what I want, and there is no game on the market today that even comes close to my vision, so I guess that's also why it's been more of a concept then a game for many years. Yes I've been developing but more prototyping and learning. It's only recently in the past year with broadband become very common place, Linux reaching a new maturity level, database clustering and grid computing topping the scale, where I can finally achieve what I've wanted.

I know I might sound like a dreamer and someone who's unrealistic, but I do have credible references behind me.

These are me:

Oracle 2005 CTO Award: http://www.oracle.com/technology/oramag/oracle/05-nov/o65awards.html#grantanand

Info World CTO 2005 Award: http://www.infoworld.com/reports/15SRcto2005.html

I'd love to take a look at your particle system, thanks for offering.

[Edited by - QuadMV on March 15, 2006 10:42:14 PM]

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hplus0603    11356
Quote:
 Original post by QuadMVI’m really getting frustrated. I’ve been working on my own engine for a long time now, but I really don’t want to be working on an engine. I want to be working on my game, but I have specific requirements and years ago when I started no engine had the features I really wanted.

One of the hardest skills in life is to learn to compromise. If you want free-roaming terrain, but can't get it, but you want to make a game even more than making a terrain engine, then make a game without free-roaming terrain. You can always add that feature later. Same thing for every other feature: do you REALLY want that feature more than you want to make a game?

Quote:
 1. Models: Reliable modeling system for animated and non-animated objects. I originally wanted to use .X models, which I’m currently using, but I’m finding that the exporter is terrible, especially for animation. I’d love something like granny, but it’s too expensive.

Cal3D comes to mind. However, .X isn't that bad -- it depends on which modeler you're using (Max, Maya, Milkshape, ... ?) and which exporter (Microsoft's, PandaDX, something else?)

Quote:
 a. I’m particularly fond of the way HL2 and Quake 4 animate the upper torso when you move the mouse while keeping the lower torso fixed. This isn’t so much an animation as they are moving the bones connected to the gun as the gun swings around. It’s a great effect

It's very easy to implement on top of .X models, too. You just fix up the spine twist after you evaluate the animation for some specific time. Or, perhaps, you can play an animation that twists left/right, and add that on top of the other animation, moving the position in time of the twist animation based on how you want to twist the torso.

Quote:
 3. Particles: I need a good particle system to bring the world to life. Smoke, fire, rain, clouds, vapor trails, etc.

Particles are relatively easy. I actually wrote a fairly re-usable particle system back in the CarWorld demo days. It sits on top of OpenGL, but you can probably slot it into DirectX with some work (it knows about vertex buffer-like things). IIRC, it uses XML to configure the particle effects; using the XMLSCAN fast XML loading library. It also has a small dependency on ODE that can easily be taken out.

Quote:
 Instead of getting a formal rendering engine that would limit my abilities to use what I’ve already done, I think maybe what I want are libraries, preferably open source, but I’d even pay if it’s not too expensive.

Why don't you make a mod to a game such as something based on Source? Or buy Torque? Or use OpenSG, or Ogre, which are two relatively high quality renderers? (OpenSG is GL only, though) Note that Ogre is ONLY a renderer; it is NOT an engine (contrary to popular belief).

Again: do you REALLY want to make a game, or do you absolutely have to have everything to your specific specifications?

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circlesoft    1178
Quote:
 Original post by hplus0603Again: do you REALLY want to make a game, or do you absolutely have to have everything to your specific specifications?

Quote:
 Thanks guys, but I've thoroughly researched Ogre, irrLicht and Torque as well as others. Although these all have their benefits, none have the features I'm looking for and after evaluating the amount of time it would take to integrate my required feature set into them, I'm believing it'll be less work to add the aforementioned features into my engine and will give me more control and flexibility as I know my engine very well.

Along H's train of thought - even commercical engines are modified by their licensees on a regular basis. The reasons for this can vary, but they are generally things like:

- Integrating some new middleware package (animation, physics, ect)
- New graphics techniques/algorithms
- Engine changes to support gameplay additions

Exactly

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Quote:
 Original post by QuadMV 3. Particles: I need a good particle system to bring the world to life. Smoke, fire, rain, clouds, vapor trails, etc.

hi QuadMV i have a particle system classes that i am using in my games , but it is not that advanced and it is written in Managed Code C# i use it for rain and smoke , if u r interested in it i can give u the classes and u can make whatever updates u want to it. but again it is made using C#

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I've got some excellent lighting & shadowing techniques implemented in my engine, but it's more suited for indoor scince outdoors, it's performance will be slow. It's in VB.NET, MDX but the bulk of it is in C HLSL, PM me if your intrested.

-Normal mapping
-Bump mapping
-Ray Parallax mapping
In one pass, with ps 2.0 and vs 1.1

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Quote:
 Original post by CadeFI've got some excellent lighting & shadowing techniques implemented in my engine, but it's more suited for indoor scince outdoors, it's performance will be slow. It's in VB.NET, MDX but the bulk of it is in C HLSL, PM me if your intrested.The HLSL shader does-Normal mapping-Bump mapping-Ray Parallax mapping-Soft shadow mappingIn one pass, with ps 2.0 and vs 1.1

we would appreciate it very much if u post ur code for the above techniques , and i am aslo interested in ur BSP collision Detection code in 3D :) hehe and if u don't mind put all the code u have in ur engin ;P

format: plain


text:
Phase transitions for p-adic Potts model on the Cayley tree of order three

Mukhamedov, Farrukh and Akin, Hasan (2013) Phase transitions for p-adic Potts model on the Cayley tree of order three. Journal of Statistical Mechanics: Theory and Experiment, 2013 (07). P07014 (1)-P07014 (30). ISSN 1742-5468 (O)

 PDF - Published Version Restricted to Registered users only Download (393kB) | Request a copy

Abstract

In the present paper, we study a phase transition problem for the q-state p-adic Potts model over the Cayley tree of order three. We consider a more general notion of p-adic Gibbs measure which depends on parameter ρ∈Qp. Such a measure is called generalized p-adic quasi Gibbs measure. When ρ equals the p-adic exponent, then it coincides with the p-adic Gibbs measure. When ρ = p, then it coincides with the p-adic quasi Gibbs measure. Therefore, we investigate two regimes with respect to the value of |ρ|p. Namely, in the first regime, one takes ρ = expp(J) for some J∈Qp, in the second one |ρ|p < 1. In each regime, we first find conditions for the existence of generalized p-adic quasi Gibbs measures. Furthermore, in the first regime, we establish the existence of the phase transition under some conditions. In the second regime, when |ρ|p,|q|p ≤ p−2 we prove the existence of a quasi phase transition. It turns out that if $\vert \rho \vert _{p}\lt \vert q-1\vert _{p}^{2}\lt 1$ and $\sqrt{-3}\in {\mathbb{Q}}_{p}$, then one finds the existence of the strong phase transition.

Item Type: Article (Journal) 5537/31745 classical phase transitions (theory) rigorous results in statistical mechanics Q Science > QA MathematicsQ Science > QC Physics Kulliyyah of Science > Department of Computational and Theoretical Sciences Dr. Farrukh Mukhamedov 24 Sep 2013 13:20 24 Sep 2013 13:20 http://irep.iium.edu.my/id/eprint/31745


text:
# We Don't Need No Stinkin' Web Frameworks

January 25, 2009

Web frameworks can be nice, but they can also get in your way. One of the pleasant side effects of implementing more and more functionality over XMPP is that we’ve eliminated the need for Web frameworks at Stanziq. This is extremely liberating.

How do we survive without them? Here are some of the ways:

• Web frameworks may offer a lot of functionality, but XMPP has a excellent, diverse set of extensions that offer a higher layer to application developers. Web frameworks are still essentially stuck on basic protocol plus ad-hoc commands. XMPP provides pubsub, presence, discovery, and much more.
• Communication is done via XMPP through Strophe instead of polling a database or using work queues. This is a step up in efficiency.
• Configuration is stored in pubsub nodes instead of relational databases. One awesome consequence of this is that all subscribers get instant notification of configuration changes, sort of like a broadcast SIGHUP.
• Front end apps, administrative code, and internal utilities are all just JavaScript. This makes them trivial to develop and test locally, and we don’t need any special deployment code.
• The whole system is more decoupled because there is no middle interfacing layer. The backend speaks XMPP, the frontend speaks XMPP, and they both use standard XMPP layer protocols to do work.

Of course, this isn’t the right fit for every problem; Web frameworks solve a lot of problem domains quite well. For those areas where it fails, it sure is nice to avoid the hassle and use an XMPP only stack.

We Don't Need No Stinkin' Web Frameworks - January 25, 2009 - Jack Moffitt


text:
## Summer 2018 Graduate Student Seminar

Meeting Tuesdays at 10:30am in room WXLR A202.

 Date Speaker Title & Abstract (click the title to expand) 05/22 Joe Wells Hybrid Lattices in PU(2,1) In the 1980's Gromov and Piatetsky-Shapiro came up with a technique called "hybridization" to produce hyperbolic lattices (and in particular, nonarithmetic lattices). It has been asked whether there is an analogous technique for complex hyperbolic lattices. In this talk I'll present some recent results relating to this question and the construction of complex hyperbolic hybrids in the Picard modular groups. This is joint work with Julien Paupert. 05/29 06/05 06/12 06/19 Lauren Crider A coordinate system for the Grassmann Manifold We're going to chat about the Grassmann Manifold $G_{K,N}$ of all $K$-dimensional subspaces in $\mathbb{C}^N$. A friendly back-pocket example of the Grassmann manifold is $G_{1,N}$, which is nothing but the very familiar and very well loved projective space on $\mathbb{C}^N$. With a tiny bit of background in statistical signal processing, we'll discover why we might care about the Grassmann manifold in practice, and why it may be beneficial to regard $G_{K,N}$ as rank-$K$ (orthogonal) projection operators on $\mathbb{C}^N$. We'll use the correspondence between points on $G_{K,N}$ and rank-$K$ projection operators to to develop a local coordinate system on $G_{K,N}$, so we can we can exploit probability measures on the manifold itself. 06/26 Joe Sadow [Title TBD] [Abstract TBD] 07/02 Scott [Title TBD] [Abstract TBD] 07/09 David Polletta [Title TBD] [Abstract TBD] 07/16 Mary Cook [Title TBD] [Abstract TBD] 07/23 [Title TBD] [Abstract TBD] 07/30 Sarah El Jamous* [Title TBD] [Abstract TBD]

*unconfirmed


text:
# PSD of linearly modulated signal using autocorrelation?

Consider a signal $$v(t)$$ given by $$v(t)=\sum_{n=-\infty}^{\infty} b[n]p(t-nT).$$ Assume that $$b[n]$$ is uncorrelated with zero mean, i.e. $$\mathbb{E}[b[n]b^*[m]]=\mathbb{E}[|b[n]|^2]\delta[n-m]$$ and $$\mathbb{E}[b[n]]=0$$.

How can one show, using the autocorrelation of $$v(t)$$, that the PSD of $$v(t)$$ is given by the following?

$$S_{v}(f)=\frac{\mathbb{E}[|b[n]|^2]}{T}|P(f)|^2$$

• The derivation of this result is given in almost any textbook on digital communications. – Matt L. Nov 4 '20 at 17:12


text:
kidzsearch.com > wiki

# Public

A public mostly means a group people.

In communication science and public relations, "public" mostly means people.[1][2] The meaning of this is different than other ideas, such as gatherings in social life to talk about people (public sphere).[1] The meaning of this is also talked about in the learning of government (political science), the learning of how humans think (psychology), and the learning of giving things to people (marketing). This word's meaning is very hard to make, as people think that public has different meanings.[3]

## How the word is created

The word "public" comes from the Latin publicus, or "of the people".

## Different meanings

In the learning of government (politics), "public" means a group of people who are related to government (leader group). In psychology and public relations, public has even more different meanings.

### Meaning in psychology

John Dewey created the first real meaning of “public”.

In the year of 1929, John Dewey had[4] the meaning of "public" as a group of people who answer the same problem. This means that this meaning is about problems (situational).[3] This definition of "public" with "problem" is so misunderstood that people made a whole new learning place, called as "the idea of the public being about problems" (situational theory of publics) created by James E Gruning,[5] who was so into "the idea of the public being about problems” that he also thought of “the idea of the public not being about problems", and so made sets that put the ideas of the meaning of public in order. This includes "the idea of a public without a problem" (nonpublics), "the idea of public with a problem" (latent publics), and "the idea of public who know they have a problem" (active publics).[6]

### Meaning in public relations

In this meaning, the meaning of “public” is not someone who likes business (stakeholder) or a system of getting and giving things for money (market). This meaning of "public" here is that it is a part of a group of multiple people who like business (stakeholder) who all need to solve a problem. This is not a market because it does not have any money moving system (exchange system), and that a "public" is created by itself (self-forming) and puts itself in order by itself (self-organizing).[2] The people who are in public relations do things for the "public". People who are needed to make a group's dreams come true are named as "target publics", and people that help the target publics are named as "influentials". Influentials are important, because they give answers to the target public's problems. The "target publics" are also important, because their answers to the government problems (like electoral votes) are very important.[7]

The public also has rules of being in the public ("social norms"), that play a major role in how information is moved.

### Situational or non-situational meaning

Problems, such as the one above, are important in the situational meaning of “public”.

Public relations theory shows that the meaning of publics is situational, according to John Dewey and James E. Gruning, and is simply a group of people. According to Gabriel M. Vasquez, a public has people that all know about their common problem and all try to solve that problem (“homo narrans” [Latin for "storytelling human"]), and create a list of problems to be solved (agenda-building).[8] For example, Schools are commonly talked about for their agenda-building, on whether they should teach about religion or not (secular).[9] Some people think publics are about the government (political) and last forever.

But, other people think that the meaning of public is non-situational. Kirk Hallahan, professor at Colorado State University, thinks that the meaning of public is about another organization, and has public as that it is people who are about (relate) to an organization, who show different amounts of activity—passivity (getting information without giving it), and who might (or might not) talk with others about their relationship with the group.

## Types of "public"

### Social publics

Social publics are people who like the same ideas or hobbies.

### Networked publics

Social media is one of the things that create networked publics.

Networked publics are social publics who are organized by the new technology. Because of this, networked publics are the result of technologies that connect people (networked technologies, like social media), and the whole result from a combination of the people in the networked public, their technologies, and their ideas.[10]

## Publics and problems

The situational theory of publics, is about the idea that publics can be used and organized by how much they know (are aware of) their common problem, and how much action the group has taken to resolve that problem. This theory shows when people communicate ideas and when the ideas are about the people who are important in solving the common problem. This theory is almost the same as John Dewey's theory of publics and Blumer's theory of publics.

### Key concepts

The five key concepts in this theory are:

1. how much the people know that have a problem (problem recognition)
2. how much the people know their actions are limited (constraint recognition)
3. amount of how much a problem affects someone (level of involvement)
4. amount of new info gotten (information seeking)
5. amount of new info processed (information processing)

### History

This theory comes from James E. Grunig's writing, "The Role of Information in Economic Decision Making" in 1966. This writing was the beginning of the situational theory of publics, as it had the first key idea, problem recognition, in the writing. Then, when he wrote about the decisions of people who own land in Columbia to become a professor, he also wrote about the second key idea, constraint recognition. He then added Herbert Krugman's idea of the third key idea, level of involvement, to explain the difference between the fourth and fifth key ideas, information seeking and information processing. After that, he wrote a book in 1984 which was named "Managing Public Relations", which further made the situational theory of publics make more sense, based on John Dewey's book, which was named "The Public and Its Problems".

### Development

Equations, such as the one shown above, helped make the situational theory of publics make more sense.

People who use the theory created equations which used the theory to organize the different types of publics, and the most real effects of communication for each public. Because these math rules were created, it made the theory more understandable and became used in a more common way in learning the theory (academic studies) and in some professional learning. This theory is like the learning of the actions of people buy things (consumer behavior), health communication, how media works (media exposure), and the communication of government related ideas (political communication), which are common in other parts of the learning of communication (communication research). But, this theory has more common key ideas and a more developed system of learning and analysis because of the equations. Because of this, it can become more common (popular) and include other smaller less common theories inside it (subsume).

### Extension

The situational theory of publics was extended to the situational theory of problem solving in 2011.

Even though the theory is well developed, it develops even more common. The theory has been used to show why people join groups who really want things to happen (activist groups), to organize the external (real, actual) and internal (perceived) parts (dimensions) of problem recognition, and to learn whether information that is used in information processing (processed information) can create publics. Also, some more research was done on the internal and external dimensions of problem recognition, constraint recognition, and level of involvement (Grunig & Hon, 1988; Grunig, 1997). The research is about whether the ideas are internal or external. The research shows that if the concepts are internal, they can be changed by communication, and that if they are external, then the holdable things that are around the person need to be changed in order for the person's concept of the variables to change (Grunig, 1997, p. 25). But, there is a small amount of research on the internal and external dimensions of the three key concepts, so there can be more studies on these concepts (Grunig, 1997). Then, in 2011, Jeong-Nam Kim and Grunig extended the theory to the situational theory of problem solving.

## References

1. Brito, R.; Bumiller, G.; Yeqiong Song (2005). "Modelling and simulation of a SFN based PLC network". International Symposium on Power Line Communications and Its Applications, 2005. (IEEE). . .
2. Bowen, Shannon; Rawlins, Brad; Martin, Thomas (2010-04-19). An Overview of the Public Relations Function. Business Expert Press. .
3. Vasquez, Gabriel M.; Taylor, Maureen. Handbook of Public Relations. Thousand Oaks, California: SAGE Publications, Inc.. pp. 139–154. .
4. Wood, JoAnn (2000). Dewey, Alice Chipman (1858-1927), educator and feminist. American National Biography Online. Oxford University Press.
5. Grunig, James E. (1983). "Washington Reporter Publics of Corporate Public Affairs Programs". Journalism Quarterly 60 (4): 603–614. . .
6. Winter, Richard (2005). "Toelichting op de preventiemedewerker". TandartsPraktijk 26 (9): 720–721. . .
7. "Publics". Encyclopedia of public relations 2. (2005). SAGE.
8. Borus, Jonathan F. (1993). "Where Have All the Residents Gone?". Harvard Review of Psychiatry 1 (1): 66–67. . .
9. Shorto, Russell (2010-02-11). "How Christian Were the Founders?". The New York Times Magazine.
10. Varnelis, Kazys (2008-10-31). "Networked Publics". MIT Press.

• Dewey, John (1927). The public and Its Problems. Chicago: Swallow Press.
• Grunig, James E. (1983). Communications behaviours and attitudes of environmental publics: Two studies. Journalism Monographs. 81. Association for Education in Journalism and Mass Communication Publications.
• Hannay, Alastair (2005) On the Public Routledge

Template-specific style sheet:

ISBN 0-415-32792-X
• "Public sphere (Öffentlichkeit)". Encyclopedia of public relations 2. (2005). SAGE.
• Jahanzsoozi, Julia (2006). "Relationships, Transparency, and Evaluation: The Implications for Public Relations". In L'Etang, Jacquie; Pieczka, Magda. Public relations: critical debates and contemporary practice. Routledge.
      .

• Kierkegaard, Søren (2002) A Literary Review; Alastair Hannay (trans.) London: Penguin

Template-specific style sheet:

ISBN 0-14-044801-2
• Lippmann, Walter. The Phantom Public (Library of Conservative Thought), Transaction Publishers; Reprint edition, January 1, 1993,

Template-specific style sheet:

ISBN 1-56000-677-3.
• Mayhew, Leon H. The New Public: Professional Communication and the Means of Social Influence, (Cambridge Cultural Social Studies), Cambridge University Press, September 28, 1997,

Template-specific style sheet:

ISBN 0-521-48493-6.
• Sennett, Richard. The Fall of Public Man W. W. Norton & Company; Reissue edition, June 1992,

Template-specific style sheet:

ISBN 0-393-30879-0.
• Toth, Elizabeth L. (2006). "Building Public Affairs Theory". In Botan, Carl H.; Hazleton, Vincent. Public relations theory II. LEA's communication series. Routledge.
      .

• Vasquez, Gabriel M. (1993). "A Homo Narrens Paradigm for Public Relations: Combining Bormann's Symbolic Convergence Theory and Grunig's Situational Theory of Publics". Journal of Public Relations Research 5: 201-216.


text:
## Problem

Problem ID: 679

Title: 24 Game

Difficulty: Hard

Description:

You are given an integer array cards of length 4. You have four cards, each containing a number in the range [1, 9]. You should arrange the numbers on these cards in a mathematical expression using the operators ['+', '-', '*', '/'] and the parentheses '(' and ')' to get the value 24.

You are restricted with the following rules:

The division operator ‘/’ represents real division, not integer division. For example, 4 / (1 - 2 / 3) = 4 / (1 / 3) = 12. Every operation done is between two numbers. In particular, we cannot use ‘-‘ as a unary operator. For example, if cards = [1, 1, 1, 1], the expression “-1 - 1 - 1 - 1” is not allowed. You cannot concatenate numbers together For example, if cards = [1, 2, 1, 2], the expression “12 + 12” is not valid. Return true if you can get such expression that evaluates to 24, and false otherwise.

## Thoughts

From a glance you can see that this is a back tracking problem but the difficulty is identify the right recurssive function.

## Solution

General Idea

As any kind parentheses are allowed, each number could be left associative or right associative (ie (x+y)+z or x + (y+z)). We solve this by recurssively splitting the numbers into two halves. By doing so we will abstract away the issue of left or right associative, as there are only two operands (ie (…) + (…)) in each iteration.

Implementation

• vector<double> helper(vecotor<double> cards)
• Given a list of cards returns all the possible values that can be evaluated form the list of cards
• Base case: when the size of cards is 1 the only possible value to be evaluated is the card itself
• Recursion:
• Iteratively split the current cards into two halves
• Call the recursive function on each half to find the list of possible evaluated
• For each possible value in the left and right half, iterate through all the operations to get a possible evaluated value for the current cards
• Iterate through the list of all possible evaluated values for the 4 provided digits and find if any of them equals to 24

Edge Cases:

• To prevent divide by 0, set the divide operation to return a dummy value if RHS is 0.
• Due to floating point precision, we will need to check 24 - epsilon < val < 24 + epsilon.

### Implementation

class Solution {
public:
vector<function<double(double, double)>> ops = {
[](double l, double r) {
return l  + r;
},
[](double l, double r) {
return l  * r;},
[](double l, double r) {
return l  - r;
},
[](double l, double r) {
if (r == 0) return 1e9;
return l  / r;
},
};

vector<double> helper(vector<double> cards) {
if (cards.size() == 1) return {cards.front()};
vector<double> ret;
for (auto it = cards.begin() + 1; it != cards.end(); it++) {
vector<double> l(cards.begin(), it);
vector<double> r(it, cards.end());
vector<double> l_s = helper(l);
vector<double> r_s = helper(r);
for (auto l_it = l_s.begin(); l_it != l_s.end(); l_it++) {
for (auto r_it = r_s.begin(); r_it != r_s.end(); r_it++) {
for (auto op : ops) {
auto val = op(*l_it, *r_it);
ret.push_back(val);
}
}
}
}
return ret;
}

bool judgePoint24(vector<int>& cards) {
vector<double> d_cards;
for (auto card : cards) d_cards.push_back(card);
sort(d_cards.begin(), d_cards.end());
vector<double> vals;
do {
auto curr_vals = helper(d_cards);
vals.insert(vals.end(), curr_vals.begin(), curr_vals.end());
} while(next_permutation(d_cards.begin(), d_cards.end()));
for (auto val : vals) if (val > 23.99 && val < 24.01) return true;
return false;
}
};


text:
How to implement Moving window with LSTM for Time Series Prediction?

I am trying to implement a moving window in my dataset. The window size=14 (for instance).After implemntinf sliding window how to prepare inputs and outputs for netwok?

    clc
clear
data = chickenpox_dataset;
data2 = [data{:}];

figure
plot(data2)
xlabel("Month")
ylabel("Cases")
title("Monthy Cases of Chickenpox")
%%
% Partition the training and test data. Train on the first 90% of the sequence
% and test on the last 10%.

numTimeStepsTrain = floor(0.9*numel(data));

dataTrain = data(1:numTimeStepsTrain+1);
dataTest = data(numTimeStepsTrain+1:end);
%% Standardize Data

mu = mean(dataTrain);
sig = std(dataTrain);

dataTrainStandardized = (dataTrain - mu) / sig;
%% Prepare Predictors and Responses
% To forecast the values of future time steps of a sequence, specify the responses
% to be the training sequences with values shifted by one time step. That is,
% at each time step of the input sequence, the LSTM network learns to predict
% the value of the next time step. The predictors are the training sequences without
% the final time step.

XTrain = dataTrainStandardized(1:end-1);
YTrain = dataTrainStandardized(2:end);
%% *Define LSTM Network Architecture*
% Create an LSTM regression network. Specify the LSTM layer to have 200 hidden
% units.

numFeatures = 1;
numResponses = 1;
numHiddenUnits = 200;

layers = [ ...
sequenceInputLayer(numFeatures)
lstmLayer(numHiddenUnits)
fullyConnectedLayer(numResponses)
regressionLayer];
%%

options = trainingOptions('adam', ...
'MaxEpochs',250, ...
'InitialLearnRate',0.005, ...
'LearnRateSchedule','piecewise', ...
'LearnRateDropPeriod',125, ...
'LearnRateDropFactor',0.2, ...
'Verbose',0, ...
'Plots','training-progress');
%% Train LSTM Network
% Train the LSTM network with the specified training options by using |trainNetwork|.

net = trainNetwork(XTrain,YTrain,layers,options);
%% Forecast Future Time Steps
% To forecast the values of multiple time steps in the future, use the |predictAndUpdateState|
% function to predict time steps one at a time and update the network state at
% each prediction. For each prediction, use the previous prediction as input to
% the function.
%
% Standardize the test data using the same parameters as the training data.

dataTestStandardized = (dataTest - mu) / sig;
XTest = dataTestStandardized(1:end-1);
%%
% To initialize the network state, first predict on the training data |XTrain|.
% Next, make the first prediction using the last time step of the training response
% |YTrain(end)|. Loop over the remaining predictions and input the previous prediction

numTimeStepsTest = numel(XTest);
for i = 2:numTimeStepsTest
end
%%
% Unstandardize the predictions using the parameters calculated earlier.

YPred = sig*YPred + mu;
%%
% The training progress plot reports the root-mean-square error (RMSE) calculated
% from the standardized data. Calculate the RMSE from the unstandardized predictions.

YTest = dataTest(2:end);
rmse = sqrt(mean((YPred-YTest).^2))
%%
% Plot the training time series with the forecasted values.

figure
plot(dataTrain(1:end-1))
hold on
idx = numTimeStepsTrain:(numTimeStepsTrain+numTimeStepsTest);
plot(idx,[data(numTimeStepsTrain) YPred],'.-')
hold off
xlabel("Month")
ylabel("Cases")
title("Forecast")
legend(["Observed" "Forecast"])
%%
% Compare the forecasted values with the test data.

figure
subplot(2,1,1)
plot(YTest)
hold on
plot(YPred,'.-')
hold off
legend(["Observed" "Forecast"])
ylabel("Cases")
title("Forecast")

subplot(2,1,2)
stem(YPred - YTest)
xlabel("Month")
ylabel("Error")
title("RMSE = " + rmse)
%% Update Network State with Observed Values
% If you have access to the actual values of time steps between predictions,
% then you can update the network state with the observed values instead of the
% predicted values.
%
% First, initialize the network state. To make predictions on a new sequence,
% reset the network state using |resetState|. Resetting the network state prevents
% previous predictions from affecting the predictions on the new data. Reset the
% network state, and then initialize the network state by predicting on the training
% data.

net = resetState(net);
%%
% Predict on each time step. For each prediction, predict the next time
% step using the observed value of the previous time step. Set the |'ExecutionEnvironment'|
% option of |predictAndUpdateState| to |'cpu'|.

YPred = [];
numTimeStepsTest = numel(XTest);
for i = 1:numTimeStepsTest
end
%%
% Unstandardize the predictions using the parameters calculated earlier.

YPred = sig*YPred + mu;
%%
% Calculate the root-mean-square error (RMSE).

rmse = sqrt(mean((YPred-YTest).^2))
%%
% Compare the forecasted values with the test data.

figure
subplot(2,1,1)
plot(YTest)
hold on
plot(YPred,'.-')
hold off
legend(["Observed" "Predicted"])
ylabel("Cases")