Actual source code: test15.c

slepc-3.18.2 2023-01-26
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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 DSPEP.\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:   PetscScalar    *K,*C,*M,*wr,*wi,z=1.0;
 22:   PetscReal      re,im,nrm,*pbc;
 23:   PetscInt       i,j,n=10,d=2,ld;
 24:   PetscViewer    viewer;
 25:   PetscBool      verbose;

 28:   SlepcInitialize(&argc,&argv,(char*)0,help);
 29:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 30:   PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type PEP - n=%" PetscInt_FMT ".\n",n);
 31:   PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);

 33:   /* Create DS object */
 34:   DSCreate(PETSC_COMM_WORLD,&ds);
 35:   DSSetType(ds,DSPEP);
 36:   DSSetFromOptions(ds);
 37:   DSPEPSetDegree(ds,d);

 39:   /* Set dimensions */
 40:   ld = n+2;  /* test leading dimension larger than n */
 41:   DSAllocate(ds,ld);
 42:   DSSetDimensions(ds,n,0,0);

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

 51:   /* Fill matrices */
 52:   DSGetArray(ds,DS_MAT_E0,&K);
 53:   for (i=0;i<n-1;i++) K[i+i*ld] = 2.0*n;
 54:   K[n-1+(n-1)*ld] = 1.0*n;
 55:   for (i=1;i<n;i++) {
 56:     K[i+(i-1)*ld] = -1.0*n;
 57:     K[(i-1)+i*ld] = -1.0*n;
 58:   }
 59:   DSRestoreArray(ds,DS_MAT_E0,&K);
 60:   DSGetArray(ds,DS_MAT_E1,&C);
 61:   C[n-1+(n-1)*ld] = 2.0*PETSC_PI/z;
 62:   DSRestoreArray(ds,DS_MAT_E1,&C);
 63:   DSGetArray(ds,DS_MAT_E2,&M);
 64:   for (i=0;i<n-1;i++) M[i+i*ld] = -4.0*PETSC_PI*PETSC_PI/n;
 65:   M[i+i*ld] = -2.0*PETSC_PI*PETSC_PI/n;
 66:   DSRestoreArray(ds,DS_MAT_E2,&M);

 68:   if (verbose) {
 69:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
 70:     DSView(ds,viewer);
 71:   }

 73:   /* Solve */
 74:   PetscMalloc2(d*n,&wr,d*n,&wi);
 75:   DSGetSlepcSC(ds,&sc);
 76:   sc->comparison    = SlepcCompareLargestReal;
 77:   sc->comparisonctx = NULL;
 78:   sc->map           = NULL;
 79:   sc->mapobj        = NULL;
 80:   DSSolve(ds,wr,wi);
 81:   DSSort(ds,wr,wi,NULL,NULL,NULL);
 82:   if (verbose) {
 83:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
 84:     DSView(ds,viewer);
 85:   }

 87:   /* Print polynomial coefficients */
 88:   PetscPrintf(PETSC_COMM_WORLD,"Polynomial coefficients (alpha,beta,gamma) =\n");
 89:   DSPEPGetCoefficients(ds,&pbc);
 90:   for (j=0;j<3;j++) {
 91:     for (i=0;i<d+1;i++) PetscViewerASCIIPrintf(viewer,"  %.5f",(double)pbc[j+3*i]);
 92:     PetscViewerASCIIPrintf(viewer,"\n");
 93:   }
 94:   PetscFree(pbc);

 96:   /* Print eigenvalues */
 97:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
 98:   for (i=0;i<d*n;i++) {
 99: #if defined(PETSC_USE_COMPLEX)
100:     re = PetscRealPart(wr[i]);
101:     im = PetscImaginaryPart(wr[i]);
102: #else
103:     re = wr[i];
104:     im = wi[i];
105: #endif
106:     if (PetscAbs(im)<1e-10) PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)re);
107:     else PetscViewerASCIIPrintf(viewer,"  %.5f%+.5fi\n",(double)re,(double)im);
108:   }

110:   /* Eigenvectors */
111:   DSVectors(ds,DS_MAT_X,NULL,NULL);  /* all eigenvectors */
112:   DSGetMat(ds,DS_MAT_X,&X);
113:   MatCreateVecs(X,NULL,&x0);
114:   MatGetColumnVector(X,x0,0);
115:   VecNorm(x0,NORM_2,&nrm);
116:   DSRestoreMat(ds,DS_MAT_X,&X);
117:   VecDestroy(&x0);
118:   PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st vector = %.3f\n",(double)nrm);
119:   if (verbose) {
120:     PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
121:     DSView(ds,viewer);
122:   }

124:   PetscFree2(wr,wi);
125:   DSDestroy(&ds);
126:   SlepcFinalize();
127:   return 0;
128: }

130: /*TEST

132:    test:
133:       suffix: 1
134:       requires: !single

136: TEST*/