GMatMatMultUzawa

This function applies B^T A^{-1} B to a vector, which is the Schur complement matrix.

#include "petscsles.h" 
#include "gsolver.h" 
int GMatMatMultUzawa(GMat mat, GVec x, GVec y)

	mat	- The grid matrix
	x	- The input grid vector

y -The output grid vector B^T A^{-1} B x