Actual source code: test13.c

slepc-3.22.1 2024-10-28
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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:   PetscFunctionBeginUser;
 40:   PetscCall(SlepcInitialize(&argc,&argv,NULL,help));
 41:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL));
 42:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,&flg));
 43:   if (!flg) n=m+2;
 44:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL));
 45:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nRectangular bidiagonal matrix, m=%" PetscInt_FMT " n=%" PetscInt_FMT "\n\n",m,n));

 47:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 48:         Generate the matrix
 49:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

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

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

 74:   PetscCall(SVDSolve(svd));
 75:   PetscCall(SVDPRIMMEGetBlockSize(svd,&bs));
 76:   PetscCall(SVDPRIMMEGetMethod(svd,&meth));
 77:   PetscCall(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:   PetscCall(SVDErrorView(svd,SVD_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD));
 83:   PetscCall(SVDDestroy(&svd));
 84:   PetscCall(MatDestroy(&A));
 85:   PetscCall(SlepcFinalize());
 86:   return 0;
 87: }

 89: /*TEST

 91:    build:
 92:       requires: primme

 94:    test:
 95:       suffix: 1
 96:       nsize: 2
 97:       args: -svd_nsv 4
 98:       requires: primme
 99:       filter: sed -e "s/2.99255/2.99254/" | sed -e "s/2.97024/2.97023/"

101: TEST*/