Actual source code: test14.c

slepc-3.16.3 2022-04-11
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  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[] = "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;

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

 45:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 46:                      Generate the matrices
 47:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

 65:   MatCreate(PETSC_COMM_WORLD,&B);
 66:   MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,m,n);
 67:   MatSetFromOptions(B);
 68:   MatSetUp(B);
 69:   MatGetOwnershipRange(B,&Istart,&Iend);
 70:   for (i=Istart;i<Iend;i++) {
 71:     col[0]=i-1; col[1]=i;
 72:     if (i==0) {
 73:       MatSetValue(B,i,col[1],valsb[1],INSERT_VALUES);
 74:     } else if (i<n) {
 75:       MatSetValues(B,1,&i,2,col,valsb,INSERT_VALUES);
 76:     } else if (i==n) {
 77:       MatSetValue(B,i,col[0],valsb[0],INSERT_VALUES);
 78:     }
 79:   }
 80:   MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
 81:   MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);

 83:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 84:          Create the singular value solver, set options and solve
 85:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 87:   SVDCreate(PETSC_COMM_WORLD,&svd);
 88:   SVDSetOperators(svd,A,NULL);
 89:   SVDSetTolerances(svd,PETSC_DEFAULT,1000);
 90:   SVDSetFromOptions(svd);
 91:   SVDSolve(svd);
 92:   SVDErrorView(svd,SVD_ERROR_RELATIVE,NULL);

 94:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 95:                        Solve with second matrix
 96:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 98:   SVDSetOperators(svd,B,NULL);
 99:   SVDSolve(svd);
100:   SVDErrorView(svd,SVD_ERROR_RELATIVE,NULL);

102:   /* Free work space */
103:   SVDDestroy(&svd);
104:   MatDestroy(&A);
105:   MatDestroy(&B);
106:   SlepcFinalize();
107:   return ierr;
108: }

110: /*TEST

112:    testset:
113:       args: -svd_nsv 3
114:       requires: !single
115:       output_file: output/test14_1.out
116:       test:
117:          suffix: 1
118:          args: -svd_type {{lanczos trlanczos lapack}}
119:       test:
120:          suffix: 1_cross
121:          args: -svd_type cross -svd_cross_explicitmatrix {{0 1}}
122:       test:
123:          suffix: 1_cyclic
124:          args: -svd_type cyclic -svd_cyclic_explicitmatrix {{0 1}}

126:    testset:
127:       args: -n 18 -svd_nsv 3
128:       requires: !single
129:       output_file: output/test14_2.out
130:       test:
131:          suffix: 2
132:          args: -svd_type {{lanczos trlanczos lapack}}
133:       test:
134:          suffix: 2_cross
135:          args: -svd_type cross -svd_cross_explicitmatrix {{0 1}}
136:       test:
137:          suffix: 2_cyclic
138:          args: -svd_type cyclic -svd_cyclic_explicitmatrix {{0 1}}

140: TEST*/