petsc-3.7.7 2017-09-25
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MatPtAP

Creates the matrix product C = P^T * A * P

Synopsis

#include "petscmat.h" 
PetscErrorCode MatPtAP(Mat A,Mat P,MatReuse scall,PetscReal fill,Mat *C)
Neighbor-wise Collective on Mat

Input Parameters

A - the matrix
P - the projection matrix
scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
fill - expected fill as ratio of nnz(C)/(nnz(A) + nnz(P)), use PETSC_DEFAULT if you do not have a good estimate if the result is a dense matrix this is irrelevent

Output Parameters

C -the product matrix

Notes

C will be created and must be destroyed by the user with MatDestroy().

This routine is currently only implemented for pairs of AIJ matrices and classes which inherit from AIJ.

See Also

MatPtAPSymbolic(), MatPtAPNumeric(), MatMatMult(), MatRARt()

Level:intermediate
Location:
src/mat/interface/matrix.c
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages

Examples

src/tao/pde_constrained/examples/tutorials/elliptic.c.html