### Copying matrices

Function: int gsl_matrix_memcpy (gsl_matrix * dest, const gsl_matrix * src)
  This function copies the elements of the matrix src into the matrix dest. The two matrices must have the same size.

Function: int gsl_matrix_swap (gsl_matrix * m1, const gsl_matrix * m2)
  This function exchanges the elements of the matrices m1 and m2 by copying. The two matrices must have the same size.