MatAXPY

Computes Y = a*X + Y.

#include "petscmat.h"  
int MatAXPY(PetscScalar *a,Mat X,Mat Y,MatStructure str)

Collective on Mat

	a	- the scalar multiplier
	X	- the first matrix
	Y	- the second matrix
	str	- either SAME_NONZERO_PATTERN or DIFFERENT_NONZERO_PATTERN

Contributed by: Matthew Knepley

Will only be efficient if one has the SAME_NONZERO_PATTERN

matrix, add