petsc-3.8.4 2018-03-24

MatCreateSubMatrixFree

Creates a reduced matrix by masking a full matrix.

#include "petsctao.h" 
#include "submatfree.h" 
PetscErrorCode MatCreateSubMatrixFree(Mat mat,IS Rows, IS Cols, Mat *J)

Collective on matrix

	mat	- matrix of arbitrary type
	Rows	- the rows that will be in the submatrix
	Cols	- the columns that will be in the submatrix

J -New matrix

The user provides the input data and is responsible for destroying this data after matrix J has been destroyed.