Date: 2021-02-01T14:41:45+00:00

Actual source code: test16.c
slepc-3.14.2 2021-02-01
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-2020, 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 pseudo-orthogonalization.\n\n";

     13: #include <slepcds.h>

     15: int main(int argc,char **argv)
     16: {
     18:   DS             ds;
     19:   PetscReal      *s,*ns;
     20:   PetscScalar    *A;
     21:   PetscInt       i,j,n=10;
     22:   PetscViewer    viewer;
     23:   PetscBool      verbose;

     25:   SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
     26:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
     27:   PetscPrintf(PETSC_COMM_WORLD,"Test pseudo-orthogonalization for GHIEP - dimension %D.\n",n);
     28:   PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);

     30:   /* Create DS object */
     31:   DSCreate(PETSC_COMM_WORLD,&ds);
     32:   DSSetType(ds,DSGHIEP);
     33:   DSSetFromOptions(ds);
     34:   DSAllocate(ds,n);
     35:   DSSetDimensions(ds,n,0,0,0);

     37:   /* Set up viewer */
     38:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
     39:   if (verbose) {
     40:     PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
     41:   }

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

     57:   /* Signature matrix */
     58:   PetscMalloc2(n,&s,n,&ns);
     59:   s[0] = -1.0;
     60:   for (i=1;i<n-1;i++) s[i]=1.0;
     61:   s[n-1] = -1.0;

     63:   /* Orthogonalize and show signature */
     64:   DSPseudoOrthogonalize(ds,DS_MAT_A,n,s,NULL,ns);
     65:   if (verbose) {
     66:     PetscPrintf(PETSC_COMM_WORLD,"After pseudo-orthogonalize - - - - - - - - -\n");
     67:     DSView(ds,viewer);
     68:   }
     69:   PetscPrintf(PETSC_COMM_WORLD,"Resulting signature:\n");
     70:   for (i=0;i<n;i++) {
     71:     PetscPrintf(PETSC_COMM_WORLD,"%g\n",(double)ns[i]);
     72:   }
     73:   PetscFree2(s,ns);

     75:   DSDestroy(&ds);
     76:   SlepcFinalize();
     77:   return ierr;
     78: }

     80: /*TEST

     82:    test:
     83:       suffix: 1

     85: TEST*/