code: public static DMatrixRMaj rectangleGaussian(int numRow , int numCol , double mean , double stdev , Random rand )
      {
          DMatrixRMaj m = new DMatrixRMaj(numRow,numCol);
          fillGaussian(m,mean,stdev,rand);
          return m;
      }
docs: <p>
  Sets each element in the matrix to a value drawn from an Gaussian distribution with the specified mean and
  standard deviation
  </p>
  
  
  @param numRow Number of rows in the new matrix.
  @param numCol Number of columns in the new matrix.
  @param mean Mean value in the distribution
  @param stdev Standard deviation in the distribution
  @param rand Random number generator used to fill the matrix.