MatStoreValues#

Stashes a copy of the matrix values; this allows, for example, reuse of the linear part of a Jacobian, while recomputing the nonlinear portion.

Synopsis#

#include "petscmat.h" 
PetscErrorCode MatStoreValues(Mat mat)

Logically Collect

Input Parameters#

  • mat - the matrix (currently only MATAIJ matrices support this option)

Common Usage, with SNESSolve()#

Create Jacobian matrix
Set linear terms into matrix
Apply boundary conditions to matrix, at this time matrix must have
final nonzero structure (i.e. setting the nonlinear terms and applying
boundary conditions again will not change the nonzero structure
ierr = MatStoreValues(mat);
Call SNESSetJacobian() with matrix
In your Jacobian routine
ierr = MatRetrieveValues(mat);
Set nonlinear terms in matrix

Common Usage without SNESSolve(), i.e. when you handle nonlinear solve yourself#

// build linear portion of Jacobian
ierr = MatStoreValues(mat);
loop over nonlinear iterations
ierr = MatRetrieveValues(mat);
// call MatSetValues(mat,...) to set nonliner portion of Jacobian
// call MatAssemblyBegin/End() on matrix
Solve linear system with Jacobian
endloop

Notes#

Matrix must already be assemblied before calling this routine Must set the matrix option MatSetOption(mat,MAT_NEW_NONZERO_LOCATIONS,PETSC_FALSE); before calling this routine.

When this is called multiple times it overwrites the previous set of stored values and does not allocated additional space.

See Also#

MatRetrieveValues()

Level#

advanced

Location#

src/mat/impls/aij/seq/aij.c

Implementations#

MatStoreValues_MPIAIJ in src/mat/impls/aij/mpi/mpiaij.c
MatStoreValues_SeqAIJ in src/mat/impls/aij/seq/aij.c
MatStoreValues_MPIBAIJ in src/mat/impls/baij/mpi/mpibaij.c
MatStoreValues_SeqBAIJ in src/mat/impls/baij/seq/baij.c
MatStoreValues_MPISBAIJ in src/mat/impls/sbaij/mpi/mpisbaij.c
MatStoreValues_SeqSBAIJ in src/mat/impls/sbaij/seq/sbaij.c
MatStoreValues_MPISELL in src/mat/impls/sell/mpi/mpisell.c
MatStoreValues_SeqSELL in src/mat/impls/sell/seq/sell.c


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