Actual source code: test4.c

slepc-3.7.4 2017-05-17
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2016, Universitat Politecnica de Valencia, Spain

  6:    This file is part of SLEPc.

  8:    SLEPc is free software: you can redistribute it and/or modify it under  the
  9:    terms of version 3 of the GNU Lesser General Public License as published by
 10:    the Free Software Foundation.

 12:    SLEPc  is  distributed in the hope that it will be useful, but WITHOUT  ANY
 13:    WARRANTY;  without even the implied warranty of MERCHANTABILITY or  FITNESS
 14:    FOR  A  PARTICULAR PURPOSE. See the GNU Lesser General Public  License  for
 15:    more details.

 17:    You  should have received a copy of the GNU Lesser General  Public  License
 18:    along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
 19:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 20: */

 22: static char help[] = "Test DSGNHEP.\n\n";

 24: #include <slepcds.h>

 28: int main(int argc,char **argv)
 29: {
 31:   DS             ds;
 32:   SlepcSC        sc;
 33:   PetscScalar    *A,*B,*X,*wr,*wi;
 34:   PetscReal      re,im,rnorm,aux;
 35:   PetscInt       i,j,n=10,ld;
 36:   PetscViewer    viewer;
 37:   PetscBool      verbose;

 39:   SlepcInitialize(&argc,&argv,(char*)0,help);
 40:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 41:   PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type GNHEP - dimension %D.\n",n);
 42:   PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);

 44:   /* Create DS object */
 45:   DSCreate(PETSC_COMM_WORLD,&ds);
 46:   DSSetType(ds,DSGNHEP);
 47:   DSSetFromOptions(ds);
 48:   ld = n+2;  /* test leading dimension larger than n */
 49:   DSAllocate(ds,ld);
 50:   DSSetDimensions(ds,n,0,0,0);

 52:   /* Set up viewer */
 53:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
 54:   PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
 55:   DSView(ds,viewer);
 56:   PetscViewerPopFormat(viewer);
 57:   if (verbose) {
 58:     PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
 59:   }

 61:   /* Fill A with Grcar matrix */
 62:   DSGetArray(ds,DS_MAT_A,&A);
 63:   PetscMemzero(A,sizeof(PetscScalar)*ld*n);
 64:   for (i=1;i<n;i++) A[i+(i-1)*ld]=-1.0;
 65:   for (j=0;j<4;j++) {
 66:     for (i=0;i<n-j;i++) A[i+(i+j)*ld]=1.0;
 67:   }
 68:   DSRestoreArray(ds,DS_MAT_A,&A);
 69:   /* Fill B with an identity matrix */
 70:   DSGetArray(ds,DS_MAT_B,&B);
 71:   PetscMemzero(B,sizeof(PetscScalar)*ld*n);
 72:   for (i=0;i<n;i++) B[i+i*ld]=1.0;
 73:   DSRestoreArray(ds,DS_MAT_B,&B);

 75:   if (verbose) {
 76:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
 77:     DSView(ds,viewer);
 78:   }

 80:   /* Solve */
 81:   PetscMalloc2(n,&wr,n,&wi);
 82:   DSGetSlepcSC(ds,&sc);
 83:   sc->comparison    = SlepcCompareLargestMagnitude;
 84:   sc->comparisonctx = NULL;
 85:   sc->map           = NULL;
 86:   sc->mapobj        = NULL;
 87:   DSSolve(ds,wr,wi);
 88:   DSSort(ds,wr,wi,NULL,NULL,NULL);
 89:   if (verbose) {
 90:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
 91:     DSView(ds,viewer);
 92:   }

 94:   /* Print eigenvalues */
 95:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
 96:   for (i=0;i<n;i++) {
 97: #if defined(PETSC_USE_COMPLEX)
 98:     re = PetscRealPart(wr[i]);
 99:     im = PetscImaginaryPart(wr[i]);
100: #else
101:     re = wr[i];
102:     im = wi[i];
103: #endif
104:     if (PetscAbs(im)<1e-10) {
105:       PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)re);
106:     } else {
107:       PetscViewerASCIIPrintf(viewer,"  %.5f%+.5fi\n",(double)re,(double)im);
108:     }
109:   }

111:   /* Eigenvectors */
112:   j = 2;
113:   DSVectors(ds,DS_MAT_X,&j,&rnorm);  /* third eigenvector */
114:   PetscPrintf(PETSC_COMM_WORLD,"Value of rnorm for 3rd vector = %.3f\n",(double)rnorm);
115:   DSVectors(ds,DS_MAT_X,NULL,NULL);  /* all eigenvectors */
116:   j = 0;
117:   rnorm = 0.0;
118:   DSGetArray(ds,DS_MAT_X,&X);
119:   for (i=0;i<n;i++) {
120: #if defined(PETSC_USE_COMPLEX)
121:     aux = PetscAbsScalar(X[i+j*ld]);
122: #else
123:     if (PetscAbs(wi[j])==0.0) aux = PetscAbsScalar(X[i+j*ld]);
124:     else aux = SlepcAbsEigenvalue(X[i+j*ld],X[i+(j+1)*ld]);
125: #endif
126:     rnorm += aux*aux;
127:   }
128:   DSRestoreArray(ds,DS_MAT_X,&X);
129:   rnorm = PetscSqrtReal(rnorm);
130:   PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st vector = %.3f\n",(double)rnorm);
131:   if (verbose) {
132:     PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
133:     DSView(ds,viewer);
134:   }

136:   PetscFree2(wr,wi);
137:   DSDestroy(&ds);
138:   SlepcFinalize();
139:   return ierr;
140: }