Actual source code: test13.c

slepc-3.15.1 2021-05-28
Report Typos and Errors
  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2021, 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;
 38:   PetscErrorCode  ierr;

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

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

 51:   MatCreate(PETSC_COMM_WORLD,&A);
 52:   MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,m,n);
 53:   MatSetFromOptions(A);
 54:   MatSetUp(A);
 55:   MatGetOwnershipRange(A,&Istart,&Iend);
 56:   for (i=Istart;i<Iend;i++) {
 57:     col[0]=i; col[1]=i+1;
 58:     if (i<n-1) {
 59:       MatSetValues(A,1,&i,2,col,value,INSERT_VALUES);
 60:     } else if (i==n-1) {
 61:       MatSetValue(A,i,col[0],value[0],INSERT_VALUES);
 62:     }
 63:   }
 64:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
 65:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

 67:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 68:         Compute singular values
 69:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 71:   SVDCreate(PETSC_COMM_WORLD,&svd);
 72:   SVDSetOperators(svd,A,NULL);
 73:   SVDSetType(svd,SVDPRIMME);
 74:   SVDPRIMMESetBlockSize(svd,4);
 75:   SVDPRIMMESetMethod(svd,SVD_PRIMME_HYBRID);
 76:   SVDSetFromOptions(svd);

 78:   SVDSolve(svd);
 79:   SVDPRIMMEGetBlockSize(svd,&bs);
 80:   SVDPRIMMEGetMethod(svd,&meth);
 81:   PetscPrintf(PETSC_COMM_WORLD," PRIMME: using block size %D, method %s\n",bs,SVDPRIMMEMethods[meth]);

 83:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 84:                     Display solution and clean up
 85:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 86:   SVDErrorView(svd,SVD_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
 87:   SVDDestroy(&svd);
 88:   MatDestroy(&A);
 89:   SlepcFinalize();
 90:   return ierr;
 91: }

 93: /*TEST

 95:    build:
 96:       requires: primme

 98:    test:
 99:       suffix: 1
100:       args: -svd_nsv 4
101:       requires: primme
102:       filter: sed -e "s/2.99255/2.99254/"

104: TEST*/