Date: 2022-08-09T09:05:46+00:00

Actual source code: test14.c
slepc-3.17.2 2022-08-09
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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[] = "Tests multiple calls to SVDSolve with equal matrix size.\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 two rectangular bidiagonal matrices

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

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

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

     44:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     45:                      Generate the matrices
     46:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

     61:   MatCreate(PETSC_COMM_WORLD,&B);
     62:   MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,m,n);
     63:   MatSetFromOptions(B);
     64:   MatSetUp(B);
     65:   MatGetOwnershipRange(B,&Istart,&Iend);
     66:   for (i=Istart;i<Iend;i++) {
     67:     col[0]=i-1; col[1]=i;
     68:     if (i==0) MatSetValue(B,i,col[1],valsb[1],INSERT_VALUES);
     69:     else if (i<n) MatSetValues(B,1,&i,2,col,valsb,INSERT_VALUES);
     70:     else if (i==n) MatSetValue(B,i,col[0],valsb[0],INSERT_VALUES);
     71:   }
     72:   MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
     73:   MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);

     75:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     76:          Create the singular value solver, set options and solve
     77:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     79:   SVDCreate(PETSC_COMM_WORLD,&svd);
     80:   SVDSetOperators(svd,A,NULL);
     81:   SVDSetTolerances(svd,PETSC_DEFAULT,1000);
     82:   SVDSetFromOptions(svd);
     83:   SVDSolve(svd);
     84:   SVDErrorView(svd,SVD_ERROR_RELATIVE,NULL);

     86:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     87:                        Solve with second matrix
     88:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     90:   SVDSetOperators(svd,B,NULL);
     91:   SVDSolve(svd);
     92:   SVDErrorView(svd,SVD_ERROR_RELATIVE,NULL);

     94:   /* Free work space */
     95:   SVDDestroy(&svd);
     96:   MatDestroy(&A);
     97:   MatDestroy(&B);
     98:   SlepcFinalize();
     99:   return 0;
    100: }

    102: /*TEST

    104:    testset:
    105:       args: -svd_nsv 3
    106:       requires: !single
    107:       output_file: output/test14_1.out
    108:       test:
    109:          suffix: 1
    110:          args: -svd_type {{lanczos trlanczos lapack}}
    111:       test:
    112:          suffix: 1_cross
    113:          args: -svd_type cross -svd_cross_explicitmatrix {{0 1}}
    114:       test:
    115:          suffix: 1_cyclic
    116:          args: -svd_type cyclic -svd_cyclic_explicitmatrix {{0 1}}

    118:    testset:
    119:       args: -n 18 -svd_nsv 3
    120:       requires: !single
    121:       output_file: output/test14_2.out
    122:       test:
    123:          suffix: 2
    124:          args: -svd_type {{lanczos trlanczos lapack}}
    125:       test:
    126:          suffix: 2_cross
    127:          args: -svd_type cross -svd_cross_explicitmatrix {{0 1}}
    128:       test:
    129:          suffix: 2_cyclic
    130:          args: -svd_type cyclic -svd_cyclic_explicitmatrix {{0 1}}

    132: TEST*/