Actual source code: test15.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[] = "Tests user interface for TRLANCZOS with GSVD.\n\n"
 12:   "The command line options are:\n"
 13:   "  -m <m>, where <m> = number of rows of A.\n"
 14:   "  -n <n>, where <n> = number of columns of A.\n"
 15:   "  -p <p>, where <p> = number of rows of B.\n\n";

 17: #include <slepcsvd.h>

 19: int main(int argc,char **argv)
 20: {
 21:   Mat                 A,B;
 22:   SVD                 svd;
 23:   KSP                 ksp;
 24:   PC                  pc;
 25:   PetscInt            m=15,n=20,p=21,i,j,d,Istart,Iend;
 26:   PetscReal           keep;
 27:   PetscBool           flg,lock;
 28:   SVDTRLanczosGBidiag bidiag;

 30:   SlepcInitialize(&argc,&argv,(char*)0,help);
 31:   PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
 32:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 33:   PetscOptionsGetInt(NULL,NULL,"-p",&p,NULL);
 34:   PetscPrintf(PETSC_COMM_WORLD,"\nGeneralized singular value decomposition, (%" PetscInt_FMT "+%" PetscInt_FMT ")x%" PetscInt_FMT "\n\n",m,p,n);

 36:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 37:                      Generate the matrices
 38:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 40:   MatCreate(PETSC_COMM_WORLD,&A);
 41:   MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,m,n);
 42:   MatSetFromOptions(A);
 43:   MatSetUp(A);

 45:   MatGetOwnershipRange(A,&Istart,&Iend);
 46:   for (i=Istart;i<Iend;i++) {
 47:     if (i>0 && i-1<n) MatSetValue(A,i,i-1,-1.0,INSERT_VALUES);
 48:     if (i+1<n) MatSetValue(A,i,i+1,-1.0,INSERT_VALUES);
 49:     if (i<n) MatSetValue(A,i,i,2.0,INSERT_VALUES);
 50:     if (i>n) MatSetValue(A,i,n-1,1.0,INSERT_VALUES);
 51:   }
 52:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
 53:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

 55:   MatCreate(PETSC_COMM_WORLD,&B);
 56:   MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,p,n);
 57:   MatSetFromOptions(B);
 58:   MatSetUp(B);

 60:   MatGetOwnershipRange(B,&Istart,&Iend);
 61:   d = PetscMax(0,n-p);
 62:   for (i=Istart;i<Iend;i++) {
 63:     for (j=0;j<=PetscMin(i,n-1);j++) MatSetValue(B,i,j+d,1.0,INSERT_VALUES);
 64:   }
 65:   MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
 66:   MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);

 68:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 69:          Create the singular value solver, set options and solve
 70:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 72:   SVDCreate(PETSC_COMM_WORLD,&svd);
 73:   SVDSetOperators(svd,A,B);
 74:   SVDSetProblemType(svd,SVD_GENERALIZED);
 75:   SVDSetDimensions(svd,4,PETSC_DEFAULT,PETSC_DEFAULT);
 76:   SVDSetConvergenceTest(svd,SVD_CONV_NORM);

 78:   SVDSetType(svd,SVDTRLANCZOS);
 79:   SVDTRLanczosSetGBidiag(svd,SVD_TRLANCZOS_GBIDIAG_UPPER);

 81:   /* create a standalone KSP with appropriate settings */
 82:   KSPCreate(PETSC_COMM_WORLD,&ksp);
 83:   KSPSetType(ksp,KSPLSQR);
 84:   KSPGetPC(ksp,&pc);
 85:   PCSetType(pc,PCNONE);
 86:   KSPSetTolerances(ksp,PETSC_SMALL,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
 87:   KSPSetFromOptions(ksp);
 88:   SVDTRLanczosSetKSP(svd,ksp);
 89:   SVDTRLanczosSetRestart(svd,0.4);
 90:   SVDTRLanczosSetLocking(svd,PETSC_TRUE);

 92:   SVDSetFromOptions(svd);

 94:   PetscObjectTypeCompare((PetscObject)svd,SVDTRLANCZOS,&flg);
 95:   if (flg) {
 96:     SVDTRLanczosGetGBidiag(svd,&bidiag);
 97:     PetscPrintf(PETSC_COMM_WORLD,"TRLANCZOS: using %s bidiagonalization\n",SVDTRLanczosGBidiags[bidiag]);
 98:     SVDTRLanczosGetRestart(svd,&keep);
 99:     SVDTRLanczosGetLocking(svd,&lock);
100:     PetscPrintf(PETSC_COMM_WORLD,"TRLANCZOS: restarting parameter %.2f %s\n",(double)keep,lock?"(locking)":"");
101:   }

103:   SVDSolve(svd);
104:   SVDErrorView(svd,SVD_ERROR_NORM,NULL);

106:   /* Free work space */
107:   SVDDestroy(&svd);
108:   KSPDestroy(&ksp);
109:   MatDestroy(&A);
110:   MatDestroy(&B);
111:   SlepcFinalize();
112:   return 0;
113: }

115: /*TEST

117:    test:
118:       suffix: 1
119:       args: -svd_trlanczos_gbidiag {{single upper lower}}
120:       filter: grep -v "TRLANCZOS: using"
121:       requires: !single

123:    test:
124:       suffix: 2
125:       args: -m 6 -n 12 -p 12 -svd_trlanczos_restart .7
126:       requires: !single

128: TEST*/