Date: 2017-05-17T08:24:54+00:00

Actual source code: test12.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 DSNEP.\n\n";

     24: #include <slepcds.h>

     28: int main(int argc,char **argv)
     29: {
     31:   DS             ds;
     32:   FN             f1,f2,f3,funs[3];
     33:   PetscScalar    *Id,*A,*B,*wr,*wi,coeffs[2];
     34:   PetscReal      tau=0.001,h,a=20,xi,re,im;
     35:   PetscInt       i,n=10,ld,nev;
     36:   PetscViewer    viewer;
     37:   PetscBool      verbose;

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

     45:   /* Create DS object */
     46:   DSCreate(PETSC_COMM_WORLD,&ds);
     47:   DSSetType(ds,DSNEP);
     48:   DSSetFromOptions(ds);

     50:   /* Set functions (prior to DSAllocate) */
     51:   FNCreate(PETSC_COMM_WORLD,&f1);
     52:   FNSetType(f1,FNRATIONAL);
     53:   coeffs[0] = -1.0; coeffs[1] = 0.0;
     54:   FNRationalSetNumerator(f1,2,coeffs);

     56:   FNCreate(PETSC_COMM_WORLD,&f2);
     57:   FNSetType(f2,FNRATIONAL);
     58:   coeffs[0] = 1.0;
     59:   FNRationalSetNumerator(f2,1,coeffs);

     61:   FNCreate(PETSC_COMM_WORLD,&f3);
     62:   FNSetType(f3,FNEXP);
     63:   FNSetScale(f3,-tau,1.0);

     65:   funs[0] = f1;
     66:   funs[1] = f2;
     67:   funs[2] = f3;
     68:   DSNEPSetFN(ds,3,funs);

     70:   /* Set dimensions */
     71:   ld = n+2;  /* test leading dimension larger than n */
     72:   DSAllocate(ds,ld);
     73:   DSSetDimensions(ds,n,0,0,0);

     75:   /* Set up viewer */
     76:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
     77:   PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
     78:   DSView(ds,viewer);
     79:   PetscViewerPopFormat(viewer);
     80:   if (verbose) {
     81:     PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
     82:   }

     84:   /* Fill matrices */
     85:   DSGetArray(ds,DS_MAT_E0,&Id);
     86:   for (i=0;i<n;i++) Id[i+i*ld]=1.0;
     87:   DSRestoreArray(ds,DS_MAT_E0,&Id);
     88:   h = PETSC_PI/(PetscReal)(n+1);
     89:   DSGetArray(ds,DS_MAT_E1,&A);
     90:   for (i=0;i<n;i++) A[i+i*ld]=-2.0/(h*h)+a;
     91:   for (i=1;i<n;i++) {
     92:     A[i+(i-1)*ld]=1.0/(h*h);
     93:     A[(i-1)+i*ld]=1.0/(h*h);
     94:   }
     95:   DSRestoreArray(ds,DS_MAT_E1,&A);
     96:   DSGetArray(ds,DS_MAT_E2,&B);
     97:   for (i=0;i<n;i++) {
     98:     xi = (i+1)*h;
     99:     B[i+i*ld] = -4.1+xi*(1.0-PetscExpReal(xi-PETSC_PI));
    100:   }
    101:   DSRestoreArray(ds,DS_MAT_E2,&B);

    103:   if (verbose) {
    104:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
    105:     DSView(ds,viewer);
    106:   }

    108:   /* Solve */
    109:   PetscMalloc2(n,&wr,n,&wi);
    110:   DSSolve(ds,wr,wi);
    111:   if (verbose) {
    112:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
    113:     DSView(ds,viewer);
    114:   }

    116:   /* Print first eigenvalue */
    117:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalue =\n");
    118:   nev = 1;
    119:   for (i=0;i<nev;i++) {
    120: #if defined(PETSC_USE_COMPLEX)
    121:     re = PetscRealPart(wr[i]);
    122:     im = PetscImaginaryPart(wr[i]);
    123: #else
    124:     re = wr[i];
    125:     im = wi[i];
    126: #endif
    127:     if (PetscAbs(im)<1e-10) {
    128:       PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)re);
    129:     } else {
    130:       PetscViewerASCIIPrintf(viewer,"  %.5f%+.5fi\n",(double)re,(double)im);
    131:     }
    132:   }

    134:   PetscFree2(wr,wi);
    135:   FNDestroy(&f1);
    136:   FNDestroy(&f2);
    137:   FNDestroy(&f3);
    138:   DSDestroy(&ds);
    139:   SlepcFinalize();
    140:   return ierr;
    141: }