Q:

Incompatible dimensions [scilab] or [Matlab]

i want to test this program with scilab, but when i run it, i get this error :
ATTENTION: Transposition of the line X vector to obtain compatible dimensions
plot2d: Wrong dimension of input arguments: Incompatible dimensions.
here is the program : 
t=0:400;
if t>=0 & t<=20 then
   v=0
else 
   v=15
end
plot(t,v)

A:

I think you are attempting to create a vector v whose values depend on the values of t. This means that where t is between 0 and 20, then v must be equal to 0, otherwise it must be equal to 15.
This code should produce what you are looking for:
t = 0:400;

v = zeros(size(t));
v(t > 20) = 15;

plot(t,v);

Actually, you have to create a zero-filled vector v of the same size of t and then, using a logical indexing, you have to set the values of v to 15 in correspondance of t being greater than 20.

