c - PETSc - MatLUFactor - 不支持此对象类型的此操作

Question

我正在尝试在 PETSc 中编写 LU 分解应用程序。我的想法是，程序将打印未因式分解的矩阵，然后打印因式分解的矩阵并计算因式分解本身所花费的时间。

我根据在互联网上找到的少量信息编写了代码(我使用 this post 中的信息来初始化我的矩阵)，但不幸的是，这还不够。我的代码可以编译，但是当我尝试运行它时，它只是发出此错误:

[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
[0]PETSC ERROR: No support for this operation for this object type
[0]PETSC ERROR: Mat type mpiaij
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
[0]PETSC ERROR: Petsc Release Version 3.5.2, Sep, 08, 2014 
[0]PETSC ERROR: ./petscLUFact on a arch-linux2-c-debug named martin-Aspire-E1-531 by martin Wed Oct 22 22:48:42 2014
[0]PETSC ERROR: Configure options 
[0]PETSC ERROR: #1 MatLUFactor() line 2715 in /home/martin/petsc-3.5.2/src/mat/interface/matrix.c
[0]PETSC ERROR: #2 main() line 49 in petscLUFact.c
[0]PETSC ERROR: ----------------End of Error Message -------send entire error message to petsc-maint@mcs.anl.gov----------
application called MPI_Abort(MPI_COMM_WORLD, 56) - process 0

===================================================================================
=   BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
=   EXIT CODE: 56
=   CLEANING UP REMAINING PROCESSES
=   YOU CAN IGNORE THE BELOW CLEANUP MESSAGES
===================================================================================

此错误是由 MatLUFactor 引起的函数，我想将其用于就地 LU 分解。问题是，我不知道我的代码到底出了什么问题。我认为，核心问题可能在于矩阵变量本身，也许是因为分配不当(我想到了 MatMPIAIJSetPreallocation 函数)，但我不确定。

我尝试将 MatLUFactor 函数替换为 MatLUFactorNumeric和 MatLUFactorSymbolic ，但它的效果比 MatLUFactor 还要差，它的误差“大”得多:-)

最后，我尝试使用以下命令启动我的程序:

mpiexec -n 4 ./petscLUFact

所以，如果您知道任何解决方案，我将不胜感激;-) 谢谢!

P.s.:我一直在寻找可能的解决方案，到目前为止我找到的最接近的文章是 this maillist ，但提问者使用 ParMETIS 和 SuperLU 包，据我所知，我不使用。

<小时/>

这是我的源代码:

static char help[] = "Reads a PETSc matrix and vector from a file and reorders it.\n\
    f0 <input_file> : first file to load (small system)\n\
    -f1 <input_file> : second file to load (larger system)\n\n";

#include <petscsys.h>
#include <petscmat.h>

int main( int argc, char **args ) {
    Mat             A; // 'main' matrix
    PetscInt        r = 2, c = 2; // matrix dimensions (row x col)
    PetscInt        i,j; // coordinates
    PetscInt        Istart, Iend;
    PetscInt        Ii; // counter
    PetscScalar     v; // 2-dimensional array ??? (I'm not sure)
    PetscErrorCode  ierr;

    PetscInitialize( &argc, &args, (char*)0, help );

    // Create matrix
    ierr = MatCreate( PETSC_COMM_WORLD, &A );CHKERRQ( ierr );
    ierr = MatSetSizes( A, PETSC_DECIDE, PETSC_DECIDE, r*c, r*c );CHKERRQ( ierr );
    ierr = MatSetFromOptions(A);CHKERRQ( ierr );
    ierr = MatMPIAIJSetPreallocation( A, 2, PETSC_NULL, 2, PETSC_NULL );CHKERRQ( ierr );
    ierr = MatGetOwnershipRange(A,&Istart,&Iend);CHKERRQ( ierr );

    // INIT matrix
    ierr = MatSetValue( A, 0, 0, 1, INSERT_VALUES ); CHKERRQ( ierr );
    ierr = MatSetValue( A, 0, 1, 2, INSERT_VALUES ); CHKERRQ( ierr );
    ierr = MatSetValue( A, 1, 0, 3, INSERT_VALUES ); CHKERRQ( ierr );
    ierr = MatSetValue( A, 1, 1, 1, INSERT_VALUES ); CHKERRQ( ierr );

    ierr = MatAssemblyBegin( A, MAT_FINAL_ASSEMBLY ); CHKERRQ( ierr );
    ierr = MatAssemblyEnd( A, MAT_FINAL_ASSEMBLY ); CHKERRQ( ierr );

    // Print the matrix
    ierr = MatView( A, PETSC_VIEWER_STDOUT_WORLD ); CHKERRQ( ierr );

    // -----------------
    // LU-decomposition
    // -----------------
    MatFactorInfo mfi;

    // MatFactorInfo mfi INIT
    ierr = MatFactorInfoInitialize( &mfi ); CHKERRQ( ierr );
    mfi.fill = 2;
    mfi.dtcol = 0; 

    IS rowPerm; // variable for row permutations
    IS colPerm; // variable for column permutations

    // Possible replace for MatLUFactor
    /*
    Mat Fact;
    ierr = MatLUFactorSymbolic( Fact, A, rowPerm, colPerm, &mfi );
    ierr = MatLUFactorNumeric( Fact, A, &mfi );
    */      

    // I've read somewhere, that zeros are enough for last three
    // parameters, but it doesn't work too
    //ierr = MatLUFactor( A, 0, 0, 0 ); CHKERRQ( ierr );

    ierr = MatLUFactor( A, rowPerm, colPerm, &mfi );

    ierr = MatView( A, PETSC_VIEWER_STDOUT_WORLD ); CHKERRQ( ierr );

    MatDestroy(&A);

    PetscFinalize();

    return 0;
}

这是我使用 MatLUFactorNumeric 和 MatLUFactorSymbolic 函数时的错误:

[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
[0]PETSC ERROR: No support for this operation for this object type
[0]PETSC ERROR: Matrix format mpiaij does not have a built-in PETSc LU
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
[0]PETSC ERROR: Petsc Release Version 3.5.2, Sep, 08, 2014 
[0]PETSC ERROR: ./petscLUFact on a arch-linux2-c-debug named martin-Aspire-E1-531 by martin Wed Oct 22 23:40:55 2014
[0]PETSC ERROR: Configure options 
[0]PETSC ERROR: #1 MatGetFactor() line 3961 in /home/martin/petsc-3.5.2/src/mat/interface/matrix.c
[0]PETSC ERROR: ------------------------------------------------------------------------
[0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range
[0]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger
[0]PETSC ERROR: or see http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind[0]PETSC ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS X to find memory corruption errors
[0]PETSC ERROR: likely location of problem given in stack below
[0]PETSC ERROR: ---------------------  Stack Frames ------------------------------------
[0]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,
[0]PETSC ERROR:       INSTEAD the line number of the start of the function
[0]PETSC ERROR:       is given.
[0]PETSC ERROR: [0] MatLUFactorSymbolic line 2825 /home/martin/petsc-3.5.2/src/mat/interface/matrix.c
[0]PETSC ERROR: [0] MatGetFactor line 3944 /home/martin/petsc-3.5.2/src/mat/interface/matrix.c
[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
[0]PETSC ERROR: Signal received
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
[0]PETSC ERROR: Petsc Release Version 3.5.2, Sep, 08, 2014 
[0]PETSC ERROR: ./petscLUFact on a arch-linux2-c-debug named martin-Aspire-E1-531 by martin Wed Oct 22 23:40:55 2014
[0]PETSC ERROR: Configure options 
[0]PETSC ERROR: #2 User provided function() line 0 in  unknown file
application called MPI_Abort(MPI_COMM_WORLD, 59) - process 0

===================================================================================
=   BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
=   EXIT CODE: 59
=   CLEANING UP REMAINING PROCESSES
=   YOU CAN IGNORE THE BELOW CLEANUP MESSAGES
===================================================================================

Answer 1

这是错误消息:

[0]PETSC ERROR: No support for this operation for this object type
[0]PETSC ERROR: Mat type mpiaij

因此不支持此操作，即 LU 分解，对于垫子类型 mpiaij。现在我们可以上诉online documentation ， 哪个确实说内置 LU 仅适用于顺序矩阵 (seqaij)。它还显示了可用的软件包，例如 SuperLU 和 MUMPS，可以与 PETSc 一起使用并行进行 LU 分解。这些都可以是使用自动安装

--download-superlu --download-mumps