[petsc-users] Corrrect usage of MatMumpsGetInverse()

Jan Grießer griesser.jan at googlemail.com
Mon Dec 16 10:08:10 CST 2019

Hello, everybody,
I am using PETSc version 3.12 together with MUMPS to calculate a part of an
inverse from a matrix A.  For this I used the example
mat/examples/tests/ex214.c as suggested here in the forum.  For test
purposes I read a matrix with the dimension 10x10, which only has entries
on the main diagonal, because I know the inverse of it.
But now I have a problem using the MatMumpsGetInverse() function. I get the
error message:
Error reported by MUMPS in solve phase: INFOG(1)=-47 INFO(2)=1 ACcording to
the MUMPS Docu this message tells me that I would ignored the constraint
NRHS= N. I checked the shape of spRHST but they appear to be correct.  Does
anyone see the error?
My code is appended below.
static char help[] ="Compute a part of the inverse of a sparse matrix. This
code requires that PETSc was configured with MUMPS since we are dealing
with large matrices \
    and therefore use a parallel LU factorization. We compute the inverse
by solving the equation A*X=RHS. Where A is our Matrix, X is the inverse
and RHS is the identity matrix.\
    Note that the number of columns nrhs of X can be chosen smaller than
the number of columns N in A. Therefore only a part of the inverse is
computed in X. \n \
    In this code we use a sparse representation of the RHS matrix in MUMPS
in csr format. Computation of selected entries in inv(A) is done using
MatMumpsGetInverse. \n \
    Input parameters: \n\
  -fin <input_file> : file to load \n \
                -fout <input_file> : file to load \n \
-nrhs <numberofcolumns> : Number of columns to compute \n \
                        -displ <Bool>: Print matrices to terminal \n\
    Example usage: \n \
        mpiexec -np 2 ./compute_inverse_sparse_rhs -fin
-nrhs 5 -displ";

#include <stdio.h>
#include <petscmat.h>
#include <petscviewer.h>

int main(int argc, char **args){
    PetscErrorCode ierr; // Datatype used for return error code
    PetscMPIInt size,rank; // Datatype used to represent 'int' parameters
to MPI functions.
#if defined(PETSC_HAVE_MUMPS)
    Mat A,F,spRHST; // Abstract PETSc matrix object used to manage all
linear operators in PETSc
    PetscViewer fd; // Abstract PETSc object that helps view (in ASCII,
binary, graphically etc) other PETSc objects
    PetscBool       flg1,flg2; // Logical variable. Actually an int in C.
    PetscBool displ=PETSC_FALSE; // Display matrices
    PetscInt M,N,m,n,rstart,rend,nrhs,i; // PETSc type that represents an
integer, used primarily to represent size of arrays and indexing into
    PetscScalar         v;                               // PETSc type that
represents either a double precision real number,...
    char inputfile[1][PETSC_MAX_PATH_LEN]; // Input file name
//  char outputfile[1][PETSC_MAX_PATH_LEN]; // Outputfile file name

    // Initializes PETSc and MPI. Get size and rank of MPI.
    ierr = PetscInitialize(&argc, &args, (char*)0, help);if (ierr){return
    ierr = MPI_Comm_size(PETSC_COMM_WORLD, &size);CHKERRQ(ierr);
    ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRQ(ierr);

    //Check if PETSc was configured with MUMPS. If not print error message
and exit
#if !defined(PETSC_HAVE_MUMPS)
    if (!=rank){ierr = PetscPrintf(PETSC_COMM_SELF, "This code requires
MUMPS, exit...\n");CHKERRQ(ierr);
        ierr = PetscFinalize();
        return ierr;

    // Check if displ is set. If True the matrices are printed to the
    ierr = PetscOptionsGetBool(NULL, NULL, "-displ", &displ,

    // Load matrix A from file
    ierr = PetscOptionsGetString(NULL, NULL, "-fin" ,inputfile[0],
    ierr = PetscPrintf(PETSC_COMM_WORLD, "Load matrix in: %s \n",
    ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD, inputfile[0],
    ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr);
    ierr = MatSetType(A, MATAIJ);CHKERRQ(ierr);
    ierr = MatLoad(A, fd);CHKERRQ(ierr);
    // Print matrix A
    if (displ){
        ierr = PetscPrintf(PETSC_COMM_WORLD,
        ierr = PetscPrintf(PETSC_COMM_WORLD,"Matrix A from file:\n", nrhs);
        ierr = MatView(A, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
        ierr = PetscPrintf(PETSC_COMM_WORLD, "\n");CHKERRQ(ierr);
    // Check if matrix is quadratic
    ierr = MatGetSize(A, &M, &N);CHKERRQ(ierr);
    ierr = MatGetLocalSize(A, &m, &n);CHKERRQ(ierr);
    if (M != N){
        //Macro that is called when an error has been detected.
rectangular matrix: (%d, %d)", M, N);
    ierr = MatGetOwnershipRange(A,&rstart,&rend);CHKERRQ(ierr);
    ierr = PetscPrintf(PETSC_COMM_WORLD, "---------------\n");CHKERRQ(ierr);
    ierr = PetscSynchronizedPrintf(PETSC_COMM_WORLD, "Ownership ranges for
Matrix A, rank:  %i, size: %i, rstart: %i, rend: %i \n", rank, size,
rstart, rend);CHKERRQ(ierr);
    ierr = PetscSynchronizedFlush(PETSC_COMM_WORLD,
    ierr = PetscPrintf(PETSC_COMM_WORLD, "---------------\n");CHKERRQ(ierr);

    // Set the number of columns of the inverse to be computed.
    nrhs = N;
    ierr = PetscOptionsGetInt(NULL, NULL, "-nrhs", &nrhs,

    // Create SpRHST for inv(A) with sparse RHS stored in the host.
    // PETSc does not support compressed column format which is required by
MUMPS for sparse RHS matrix,
    // thus user must create spRHST=spRHS^T and call MatMatTransposeSolve()
    // User must create B^T in sparse compressed row format on the host
processor and call MatMatTransposeSolve() to implement MUMPS' MatMatSolve().
    // MUMPS requires nrhs = N
    ierr = MatCreate(PETSC_COMM_WORLD, &spRHST);CHKERRQ(ierr);
    if (!rank){
        ierr =
        ierr =
    ierr = MatSetType(spRHST,MATAIJ);CHKERRQ(ierr);
    ierr = MatSetFromOptions(spRHST);CHKERRQ(ierr);
    ierr = MatSetUp(spRHST);CHKERRQ(ierr);
    if (!rank){
        v = 1.0;
            ierr =
    ierr = MatAssemblyBegin(spRHST,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
    ierr = MatAssemblyEnd(spRHST, MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);

    // Print matrix spRHST
    if (displ){
        ierr = PetscPrintf(PETSC_COMM_WORLD,
        ierr = PetscPrintf(PETSC_COMM_WORLD,"Matrix spRHST:\n", nrhs);
        ierr = MatView(spRHST, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
        ierr = PetscPrintf(PETSC_COMM_WORLD, "\n");CHKERRQ(ierr);

    // Print information
    ierr = PetscPrintf(PETSC_COMM_WORLD, "\nCompute %i columns of the
inverse using LU-factorization in MUMPS!\n", nrhs);

    // Factorize the Matrix using a parallel LU factorization in MUMPS
    ierr = MatGetFactor(A, MATSOLVERMUMPS, MAT_FACTOR_LU, &F);CHKERRQ(ierr);
    ierr = MatLUFactorSymbolic(F, A, NULL, NULL, NULL);CHKERRQ(ierr);
    ierr = MatLUFactorNumeric(F, A, NULL);CHKERRQ(ierr);

    // Create spRHS
    Mat spRHS = NULL;

    // Create spRHS = spRHS^T. Two matrices that share internal matrix data
    // Creates a new matrix object that behaves like A'.
    ierr = MatCreateTranspose(spRHST,&spRHS);CHKERRQ(ierr);

    // Get user-specified set of entries in inverse of A
    ierr = MatMumpsGetInverse(F,spRHS);CHKERRQ(ierr);

    if (displ){
        ierr = PetscPrintf(PETSC_COMM_WORLD,
        ierr = PetscPrintf(PETSC_COMM_WORLD,"First %D columns of inv(A)
with sparse RHS:\n", nrhs);
        ierr = MatView(spRHS,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
        ierr = PetscPrintf(PETSC_COMM_WORLD,

    // Free data structures
    ierr = MatDestroy(&A);CHKERRQ(ierr);
    ierr = MatDestroy(&spRHS);CHKERRQ(ierr);
    ierr = MatDestroy(&spRHST);CHKERRQ(ierr);
    ierr = PetscFinalize();
    return ierr;

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