Actual source code: test21.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[] = "Test DSGSVD.\n\n";

 13: #include <slepcds.h>

 15: int main(int argc,char **argv)
 16: {
 17:   DS             ds;
 18:   SlepcSC        sc;
 19:   Mat            X;
 20:   Vec            x0;
 21:   PetscReal      sigma,rnorm;
 22:   PetscScalar    *A,*B,*w;
 23:   PetscInt       i,j,k,n=15,m=10,p=10,m1,p1,ld;
 24:   PetscViewer    viewer;
 25:   PetscBool      verbose;

 27:   SlepcInitialize(&argc,&argv,(char*)0,help);
 28:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 29:   PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
 30:   PetscOptionsGetInt(NULL,NULL,"-p",&p,NULL);
 31:   PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type GSVD - dimension (%" PetscInt_FMT "+%" PetscInt_FMT ")x%" PetscInt_FMT ".\n",n,p,m);
 32:   PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);

 34:   /* Create DS object */
 35:   DSCreate(PETSC_COMM_WORLD,&ds);
 36:   DSSetType(ds,DSGSVD);
 37:   DSSetFromOptions(ds);
 38:   ld   = PetscMax(PetscMax(p,m),n)+2;  /* test leading dimension larger than n */
 39:   DSAllocate(ds,ld);
 40:   DSSetDimensions(ds,n,0,0);
 41:   DSGSVDSetDimensions(ds,m,p);
 42:   DSGSVDGetDimensions(ds,&m1,&p1);

 45:   /* Set up viewer */
 46:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
 47:   PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
 48:   DSView(ds,viewer);
 49:   PetscViewerPopFormat(viewer);

 51:   k = PetscMin(n,m);
 52:   /* Fill A with a rectangular Toeplitz matrix */
 53:   DSGetArray(ds,DS_MAT_A,&A);
 54:   for (i=0;i<k;i++) A[i+i*ld]=1.0;
 55:   for (j=1;j<3;j++) {
 56:     for (i=0;i<n-j;i++) { if ((i+j)<m) A[i+(i+j)*ld]=(PetscScalar)(j+1); }
 57:   }
 58:   for (j=1;j<n/2;j++) {
 59:     for (i=0;i<n-j;i++) { if ((i+j)<n && i<m) A[(i+j)+i*ld]=-1.0; }
 60:   }
 61:   DSRestoreArray(ds,DS_MAT_A,&A);

 63:   k = PetscMin(p,m);
 64:   /* Fill B with a shifted bidiagonal matrix */
 65:   DSGetArray(ds,DS_MAT_B,&B);
 66:   for (i=m-k;i<m;i++) {
 67:     B[i-m+k+i*ld]=2.0-1.0/(PetscScalar)(i+1);
 68:     if (i) B[i-1-m+k+i*ld]=1.0;
 69:   }
 70:   DSRestoreArray(ds,DS_MAT_B,&B);

 72:   DSSetState(ds,DS_STATE_RAW);
 73:   if (verbose) {
 74:     PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
 75:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
 76:   }
 77:   DSView(ds,viewer);

 79:   /* Solve */
 80:   PetscMalloc1(m,&w);
 81:   DSGetSlepcSC(ds,&sc);
 82:   sc->comparison    = SlepcCompareLargestReal;
 83:   sc->comparisonctx = NULL;
 84:   sc->map           = NULL;
 85:   sc->mapobj        = NULL;
 86:   DSSolve(ds,w,NULL);
 87:   DSSort(ds,w,NULL,NULL,NULL,NULL);
 88:   DSSynchronize(ds,w,NULL);
 89:   if (verbose) {
 90:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
 91:     DSView(ds,viewer);
 92:   }
 93:   /* Print singular values */
 94:   PetscPrintf(PETSC_COMM_WORLD,"Computed singular values =\n");
 95:   DSGetDimensions(ds,NULL,NULL,NULL,&k);
 96:   for (i=0;i<k;i++) {
 97:     sigma = PetscRealPart(w[i]);
 98:     PetscViewerASCIIPrintf(viewer,"  %g\n",(double)sigma);
 99:   }

101:   /* Singular vectors */
102:   DSVectors(ds,DS_MAT_X,NULL,NULL);  /* all singular vectors */
103:   DSGetMat(ds,DS_MAT_X,&X);
104:   MatCreateVecs(X,NULL,&x0);
105:   MatGetColumnVector(X,x0,0);
106:   VecNorm(x0,NORM_2,&rnorm);
107:   MatDestroy(&X);
108:   VecDestroy(&x0);
109:   PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st X vector = %.3f\n",(double)rnorm);

111:   DSGetMat(ds,DS_MAT_U,&X);
112:   MatCreateVecs(X,NULL,&x0);
113:   MatGetColumnVector(X,x0,0);
114:   VecNorm(x0,NORM_2,&rnorm);
115:   MatDestroy(&X);
116:   VecDestroy(&x0);
117:   if (PetscAbs(rnorm-1.0)>10*PETSC_MACHINE_EPSILON) PetscPrintf(PETSC_COMM_WORLD,"Warning: the 1st U vector has norm %g\n",(double)rnorm);

119:   DSGetMat(ds,DS_MAT_V,&X);
120:   MatCreateVecs(X,NULL,&x0);
121:   MatGetColumnVector(X,x0,0);
122:   VecNorm(x0,NORM_2,&rnorm);
123:   MatDestroy(&X);
124:   VecDestroy(&x0);
125:   if (PetscAbs(rnorm-1.0)>10*PETSC_MACHINE_EPSILON) PetscPrintf(PETSC_COMM_WORLD,"Warning: the 1st V vector has norm %g\n",(double)rnorm);

127:   PetscFree(w);
128:   DSDestroy(&ds);
129:   SlepcFinalize();
130:   return 0;
131: }

133: /*TEST

135:    testset:
136:       output_file: output/test21_1.out
137:       requires: !single
138:       nsize: {{1 2 3}}
139:       filter: grep -v "parallel operation mode" | grep -v "MPI processes"
140:       test:
141:          suffix: 1
142:          args: -ds_parallel redundant
143:       test:
144:          suffix: 2
145:          args: -ds_parallel synchronized

147: TEST*/