Actual source code: test2.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 DSHEP.\n\n";

 13: #include <slepcds.h>

 15: int main(int argc,char **argv)
 16: {
 17:   DS             ds;
 18:   SlepcSC        sc;
 19:   PetscScalar    *A,*X,*Q,*eig,d;
 20:   PetscReal      rnorm,aux;
 21:   PetscInt       i,j,n=10,ld;
 22:   PetscViewer    viewer;
 23:   PetscBool      verbose,extrarow;

 25:   SlepcInitialize(&argc,&argv,(char*)0,help);
 26:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 27:   PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type HEP - dimension %" PetscInt_FMT ".\n",n);
 28:   PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);
 29:   PetscOptionsHasName(NULL,NULL,"-extrarow",&extrarow);

 31:   /* Create DS object */
 32:   DSCreate(PETSC_COMM_WORLD,&ds);
 33:   DSSetType(ds,DSHEP);
 34:   DSSetFromOptions(ds);
 35:   ld = n+2;  /* test leading dimension larger than n */
 36:   DSAllocate(ds,ld);
 37:   DSSetDimensions(ds,n,0,0);
 38:   DSSetExtraRow(ds,extrarow);

 40:   /* Set up viewer */
 41:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
 42:   PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
 43:   DSView(ds,viewer);
 44:   PetscViewerPopFormat(viewer);
 45:   if (verbose) PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);

 47:   /* Fill with a symmetric Toeplitz matrix */
 48:   DSGetArray(ds,DS_MAT_A,&A);
 49:   for (i=0;i<n;i++) A[i+i*ld]=2.0;
 50:   for (j=1;j<3;j++) {
 51:     for (i=0;i<n-j;i++) { A[i+(i+j)*ld]=1.0; A[(i+j)+i*ld]=1.0; }
 52:   }
 53:   if (extrarow) { A[n+(n-2)*ld]=1.0; A[n+(n-1)*ld]=1.0; }
 54:   DSRestoreArray(ds,DS_MAT_A,&A);
 55:   DSSetState(ds,DS_STATE_RAW);
 56:   if (verbose) {
 57:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
 58:     DSView(ds,viewer);
 59:   }

 61:   /* Solve */
 62:   PetscMalloc1(n,&eig);
 63:   DSGetSlepcSC(ds,&sc);
 64:   sc->comparison    = SlepcCompareLargestMagnitude;
 65:   sc->comparisonctx = NULL;
 66:   sc->map           = NULL;
 67:   sc->mapobj        = NULL;
 68:   DSSolve(ds,eig,NULL);
 69:   DSSort(ds,eig,NULL,NULL,NULL,NULL);
 70:   if (extrarow) DSUpdateExtraRow(ds);
 71:   if (verbose) {
 72:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
 73:     DSView(ds,viewer);
 74:   }

 76:   /* Print eigenvalues */
 77:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
 78:   for (i=0;i<n;i++) PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)PetscRealPart(eig[i]));

 80:   if (extrarow) {
 81:     /* Check that extra row is correct */
 82:     DSGetArray(ds,DS_MAT_A,&A);
 83:     DSGetArray(ds,DS_MAT_Q,&Q);
 84:     d = 0.0;
 85:     for (i=0;i<n;i++) d += A[n+i*ld]-Q[n-2+i*ld]-Q[n-1+i*ld];
 86:     if (PetscAbsScalar(d)>10*PETSC_MACHINE_EPSILON) PetscPrintf(PETSC_COMM_WORLD,"Warning: there is a mismatch in the extra row of %g\n",(double)PetscAbsScalar(d));
 87:     DSRestoreArray(ds,DS_MAT_A,&A);
 88:     DSRestoreArray(ds,DS_MAT_Q,&Q);
 89:   }

 91:   /* Eigenvectors */
 92:   j = 2;
 93:   DSVectors(ds,DS_MAT_X,&j,&rnorm);  /* third eigenvector */
 94:   PetscPrintf(PETSC_COMM_WORLD,"Value of rnorm for 3rd vector = %.3f\n",(double)rnorm);
 95:   DSVectors(ds,DS_MAT_X,NULL,NULL);  /* all eigenvectors */
 96:   j = 0;
 97:   rnorm = 0.0;
 98:   DSGetArray(ds,DS_MAT_X,&X);
 99:   for (i=0;i<n;i++) {
100:     aux = PetscAbsScalar(X[i+j*ld]);
101:     rnorm += aux*aux;
102:   }
103:   DSRestoreArray(ds,DS_MAT_X,&X);
104:   rnorm = PetscSqrtReal(rnorm);
105:   PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st vector = %.3f\n",(double)rnorm);
106:   if (verbose) {
107:     PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
108:     DSView(ds,viewer);
109:   }

111:   PetscFree(eig);
112:   DSDestroy(&ds);
113:   SlepcFinalize();
114:   return 0;
115: }

117: /*TEST

119:    testset:
120:       args: -n 12 -ds_method {{0 1 2}}
121:       filter: grep -v "solving the problem" | sed -e "s/extrarow//"
122:       output_file: output/test2_1.out
123:       requires: !single
124:       test:
125:          suffix: 1
126:       test:
127:          suffix: 2
128:          args: -extrarow

130: TEST*/