Date: 2022-03-31T15:29:22+00:00

Actual source code: test13.c
slepc-3.17.0 2022-03-31
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain

      6:    This file is part of SLEPc.
      7:    SLEPc is distributed under a 2-clause BSD license (see LICENSE).
      8:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      9: */

     11: static char help[] = "Test interface to external package PRIMME.\n\n"
     12:   "The command line options are:\n"
     13:   "  -m <m>, where <m> = matrix rows.\n"
     14:   "  -n <n>, where <n> = matrix columns (defaults to m+2).\n\n";

     16: #include <slepcsvd.h>

     18: /*
     19:    This example computes the singular values of a rectangular bidiagonal matrix

     21:               |  1  2                     |
     22:               |     1  2                  |
     23:               |        1  2               |
     24:           A = |          .  .             |
     25:               |             .  .          |
     26:               |                1  2       |
     27:               |                   1  2    |
     28:  */

     30: int main(int argc,char **argv)
     31: {
     32:   Mat             A;
     33:   SVD             svd;
     34:   PetscInt        m=20,n,Istart,Iend,i,k=6,col[2],bs;
     35:   PetscScalar     value[] = { 1, 2 };
     36:   PetscBool       flg;
     37:   SVDPRIMMEMethod meth;

     39:   SlepcInitialize(&argc,&argv,(char*)0,help);
     40:   PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
     41:   PetscOptionsGetInt(NULL,NULL,"-n",&n,&flg);
     42:   if (!flg) n=m+2;
     43:   PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL);
     44:   PetscPrintf(PETSC_COMM_WORLD,"\nRectangular bidiagonal matrix, m=%" PetscInt_FMT " n=%" PetscInt_FMT "\n\n",m,n);

     46:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     47:         Generate the matrix
     48:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     50:   MatCreate(PETSC_COMM_WORLD,&A);
     51:   MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,m,n);
     52:   MatSetFromOptions(A);
     53:   MatSetUp(A);
     54:   MatGetOwnershipRange(A,&Istart,&Iend);
     55:   for (i=Istart;i<Iend;i++) {
     56:     col[0]=i; col[1]=i+1;
     57:     if (i<n-1) MatSetValues(A,1,&i,2,col,value,INSERT_VALUES);
     58:     else if (i==n-1) MatSetValue(A,i,col[0],value[0],INSERT_VALUES);
     59:   }
     60:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
     61:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

     63:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     64:         Compute singular values
     65:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     67:   SVDCreate(PETSC_COMM_WORLD,&svd);
     68:   SVDSetOperators(svd,A,NULL);
     69:   SVDSetType(svd,SVDPRIMME);
     70:   SVDPRIMMESetBlockSize(svd,4);
     71:   SVDPRIMMESetMethod(svd,SVD_PRIMME_HYBRID);
     72:   SVDSetFromOptions(svd);

     74:   SVDSolve(svd);
     75:   SVDPRIMMEGetBlockSize(svd,&bs);
     76:   SVDPRIMMEGetMethod(svd,&meth);
     77:   PetscPrintf(PETSC_COMM_WORLD," PRIMME: using block size %" PetscInt_FMT ", method %s\n",bs,SVDPRIMMEMethods[meth]);

     79:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     80:                     Display solution and clean up
     81:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
     82:   SVDErrorView(svd,SVD_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
     83:   SVDDestroy(&svd);
     84:   MatDestroy(&A);
     85:   SlepcFinalize();
     86:   return 0;
     87: }

     89: /*TEST

     91:    build:
     92:       requires: primme

     94:    test:
     95:       suffix: 1
     96:       args: -svd_nsv 4
     97:       requires: primme
     98:       filter: sed -e "s/2.99255/2.99254/"

    100: TEST*/