Date: 2023-09-05T10:18:05+00:00

Actual source code: ex49.c
slepc-3.19.2 2023-09-05
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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[] = "User-defined split preconditioner when solving a generalized eigenproblem.\n\n"
     12:   "The command line options are:\n"
     13:   "  -n <n>, where <n> = number of grid subdivisions in x dimension.\n"
     14:   "  -m <m>, where <m> = number of grid subdivisions in y dimension.\n\n";

     16: #include <slepceps.h>

     18: int main(int argc,char **argv)
     19: {
     20:   Mat            A,B,A0,B0,mats[2]; /* problem matrices and sparser approximations */
     21:   EPS            eps;               /* eigenproblem solver context */
     22:   ST             st;
     23:   PetscInt       N,n=24,m,Istart,Iend,II,i,j;
     24:   PetscBool      flag,terse;

     26:   PetscFunctionBeginUser;
     27:   PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));

     29:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
     30:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag));
     31:   if (!flag) m=n;
     32:   N = n*m;
     33:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nGHEP with split preconditioner, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m));

     35:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     36:           Compute the problem matrices A and B
     37:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     39:   PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
     40:   PetscCall(MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N));
     41:   PetscCall(MatSetFromOptions(A));
     42:   PetscCall(MatSetUp(A));

     44:   PetscCall(MatCreate(PETSC_COMM_WORLD,&B));
     45:   PetscCall(MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,N,N));
     46:   PetscCall(MatSetFromOptions(B));
     47:   PetscCall(MatSetUp(B));

     49:   PetscCall(MatGetOwnershipRange(A,&Istart,&Iend));
     50:   for (II=Istart;II<Iend;II++) {
     51:     i = II/n; j = II-i*n;
     52:     if (i>0) PetscCall(MatSetValue(A,II,II-n,-0.2,INSERT_VALUES));
     53:     if (i<m-1) PetscCall(MatSetValue(A,II,II+n,-0.2,INSERT_VALUES));
     54:     if (j>0) PetscCall(MatSetValue(A,II,II-1,-3.0,INSERT_VALUES));
     55:     if (j<n-1) PetscCall(MatSetValue(A,II,II+1,-3.0,INSERT_VALUES));
     56:     PetscCall(MatSetValue(A,II,II,7.0,INSERT_VALUES));
     57:     PetscCall(MatSetValue(B,II,II,2.0,INSERT_VALUES));
     58:   }
     59:   if (Istart==0) {
     60:     PetscCall(MatSetValue(B,0,0,6.0,INSERT_VALUES));
     61:     PetscCall(MatSetValue(B,0,1,-1.0,INSERT_VALUES));
     62:     PetscCall(MatSetValue(B,1,0,-1.0,INSERT_VALUES));
     63:     PetscCall(MatSetValue(B,1,1,1.0,INSERT_VALUES));
     64:   }
     65:   PetscCall(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY));
     66:   PetscCall(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY));
     67:   PetscCall(MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY));
     68:   PetscCall(MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY));

     70:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     71:           Compute sparser approximations A0 and B0
     72:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     74:   PetscCall(MatCreate(PETSC_COMM_WORLD,&A0));
     75:   PetscCall(MatSetSizes(A0,PETSC_DECIDE,PETSC_DECIDE,N,N));
     76:   PetscCall(MatSetFromOptions(A0));
     77:   PetscCall(MatSetUp(A0));

     79:   PetscCall(MatCreate(PETSC_COMM_WORLD,&B0));
     80:   PetscCall(MatSetSizes(B0,PETSC_DECIDE,PETSC_DECIDE,N,N));
     81:   PetscCall(MatSetFromOptions(B0));
     82:   PetscCall(MatSetUp(B0));

     84:   PetscCall(MatGetOwnershipRange(A0,&Istart,&Iend));
     85:   for (II=Istart;II<Iend;II++) {
     86:     i = II/n; j = II-i*n;
     87:     if (j>0) PetscCall(MatSetValue(A0,II,II-1,-3.0,INSERT_VALUES));
     88:     if (j<n-1) PetscCall(MatSetValue(A0,II,II+1,-3.0,INSERT_VALUES));
     89:     PetscCall(MatSetValue(A0,II,II,7.0,INSERT_VALUES));
     90:     PetscCall(MatSetValue(B0,II,II,2.0,INSERT_VALUES));
     91:   }
     92:   if (Istart==0) {
     93:     PetscCall(MatSetValue(B0,0,0,6.0,INSERT_VALUES));
     94:     PetscCall(MatSetValue(B0,1,1,1.0,INSERT_VALUES));
     95:   }
     96:   PetscCall(MatAssemblyBegin(A0,MAT_FINAL_ASSEMBLY));
     97:   PetscCall(MatAssemblyEnd(A0,MAT_FINAL_ASSEMBLY));
     98:   PetscCall(MatAssemblyBegin(B0,MAT_FINAL_ASSEMBLY));
     99:   PetscCall(MatAssemblyEnd(B0,MAT_FINAL_ASSEMBLY));

    101:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    102:                 Create the eigensolver and set various options
    103:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    105:   PetscCall(EPSCreate(PETSC_COMM_WORLD,&eps));
    106:   PetscCall(EPSSetOperators(eps,A,B));
    107:   PetscCall(EPSSetProblemType(eps,EPS_GHEP));
    108:   PetscCall(EPSGetST(eps,&st));
    109:   PetscCall(STSetType(st,STSINVERT));
    110:   mats[0] = A0; mats[1] = B0;
    111:   PetscCall(STSetSplitPreconditioner(st,2,mats,SUBSET_NONZERO_PATTERN));
    112:   PetscCall(EPSSetTarget(eps,0.0));
    113:   PetscCall(EPSSetWhichEigenpairs(eps,EPS_TARGET_MAGNITUDE));
    114:   PetscCall(EPSSetFromOptions(eps));

    116:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    117:                  Solve the eigensystem and display solution
    118:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    120:   PetscCall(EPSSolve(eps));

    122:   /* show detailed info unless -terse option is given by user */
    123:   PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
    124:   if (terse) PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
    125:   else {
    126:     PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
    127:     PetscCall(EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD));
    128:     PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD));
    129:     PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
    130:   }
    131:   PetscCall(EPSDestroy(&eps));
    132:   PetscCall(MatDestroy(&A));
    133:   PetscCall(MatDestroy(&B));
    134:   PetscCall(MatDestroy(&A0));
    135:   PetscCall(MatDestroy(&B0));
    136:   PetscCall(SlepcFinalize());
    137:   return 0;
    138: }

    140: /*TEST

    142:    testset:
    143:       args: -eps_nev 4 -terse
    144:       output_file: output/ex49_1.out
    145:       requires: !single
    146:       test:
    147:          suffix: 1
    148:       test:
    149:          suffix: 1_jd
    150:          args: -eps_type jd -st_type precond
    151:       test:
    152:          suffix: 1_lobpcg
    153:          args: -eps_type lobpcg -st_type precond -eps_smallest_real -st_shift 0.2

    155:    testset:
    156:       args: -eps_type ciss -eps_all -rg_type ellipse -rg_ellipse_center 0 -rg_ellipse_radius 0.34 -rg_ellipse_vscale .2 -terse
    157:       output_file: output/ex49_2.out
    158:       test:
    159:          suffix: 2
    160:       test:
    161:          suffix: 2_nost
    162:          args: -eps_ciss_usest 0
    163:          requires: !single
    164:       test:
    165:          suffix: 2_par
    166:          nsize: 2
    167:          args: -eps_ciss_partitions 2
    168:          requires: !single

    170: TEST*/