petsc-3.11.4 2019-09-28

MatShellSetOperation

Allows user to set a matrix operation for a shell matrix.

Synopsis

#include "petscmat.h" 
PetscErrorCode MatShellSetOperation(Mat mat,MatOperation op,void (*f)(void))

Logically Collective on Mat

Input Parameters

	mat	- the shell matrix
	op	- the name of the operation
	f	- the function that provides the operation.

Usage

     extern PetscErrorCode usermult(Mat,Vec,Vec);

     ierr = MatCreateShell(comm,m,n,M,N,ctx,&A);

     ierr = MatShellSetOperation(A,MATOP_MULT,(void(*)(void))usermult);

Notes

See the file include/petscmat.h for a complete list of matrix operations, which all have the form MATOP_<OPERATION>, where <OPERATION> is the name (in all capital letters) of the user interface routine (e.g., MatMult() -> MATOP_MULT).

All user-provided functions (except for MATOP_DESTROY) should have the same calling sequence as the usual matrix interface routines, since they are intended to be accessed via the usual matrix interface routines, e.g.,

      MatMult(Mat,Vec,Vec) -> usermult(Mat,Vec,Vec)

In particular each function MUST return an error code of 0 on success and nonzero on failure.

Within each user-defined routine, the user should call MatShellGetContext() to obtain the user-defined context that was set by MatCreateShell().

Fortran Notes

For MatCreateVecs() the user code should check if the input left or right matrix is -1 and in that case not generate a matrix. See src/mat/examples/tests/ex120f.F

Use MatSetOperation() to set an operation for any matrix type

Keywords

matrix, shell, set, operation

Level

advanced

Location

src/mat/impls/shell/shell.c

Examples