Date: 2023-01-26T12:18:08+00:00

Actual source code: test20.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 DSGNHEP with upper quasi-triangular matrix pair.\n\n";

     13: #include <slepcds.h>

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

     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 GNHEP - dimension %" PetscInt_FMT ".\n",n);
     28:   PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);

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

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

     45:   /* Fill A,B with upper quasi-triangular matrices */
     46:   DSGetArray(ds,DS_MAT_A,&A);
     47:   DSGetArray(ds,DS_MAT_B,&B);
     48:   PetscArrayzero(A,ld*n);
     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]=0.001;
     52:   }
     53:   PetscArrayzero(B,ld*n);
     54:   for (i=0;i<n;i++) B[i+i*ld]=1.0;
     55:   B[1+0*ld]=B[0+1*ld]=PETSC_MACHINE_EPSILON;
     56:   for (i=1;i<n;i+=3) {
     57:     A[i+(i-1)*ld]=-A[(i-1)+i*ld];
     58:   }
     59:   DSRestoreArray(ds,DS_MAT_A,&A);
     60:   DSRestoreArray(ds,DS_MAT_B,&B);
     61:   DSSetState(ds,DS_STATE_INTERMEDIATE);

     63:   if (verbose) {
     64:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
     65:     DSView(ds,viewer);
     66:   }

     68:   /* Eigenvectors */
     69:   j = 0;
     70:   DSVectors(ds,DS_MAT_X,&j,&rnorm);  /* first eigenvector */
     71:   PetscPrintf(PETSC_COMM_WORLD,"Value of rnorm for 2nd vector = %.3f\n",(double)rnorm);
     72:   DSVectors(ds,DS_MAT_X,NULL,NULL);  /* all eigenvectors */
     73:   j = 0;
     74:   rnorm = 0.0;
     75:   DSGetArray(ds,DS_MAT_X,&X);
     76:   for (i=0;i<n;i++) {
     77: #if defined(PETSC_USE_COMPLEX)
     78:     aux = PetscAbsScalar(X[i+j*ld]);
     79: #else
     80:     aux = SlepcAbsEigenvalue(X[i+j*ld],X[i+(j+1)*ld]);
     81: #endif
     82:     rnorm += aux*aux;
     83:   }
     84:   DSRestoreArray(ds,DS_MAT_X,&X);
     85:   rnorm = PetscSqrtReal(rnorm);
     86:   PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st columns = %.3f\n",(double)rnorm);
     87:   if (verbose) {
     88:     PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
     89:     DSView(ds,viewer);
     90:   }

     92:   DSDestroy(&ds);
     93:   SlepcFinalize();
     94:   return 0;
     95: }

     97: /*TEST

     99:    test:
    100:       suffix: 1

    102: TEST*/