Date: 2024-09-25T09:34:06+00:00

Actual source code: ex50.c
slepc-3.21.2 2024-09-25
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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 quadratic 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 <slepcpep.h>

     18: int main(int argc,char **argv)
     19: {
     20:   Mat            A[3],P[3];      /* problem matrices and split preconditioner matrices */
     21:   PEP            pep;            /* polynomial eigenproblem solver context */
     22:   ST             st;
     23:   PetscInt       N,n=10,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,"\nQuadratic Eigenproblem, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m));

     35:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     36:      Compute the matrices for (k^2*A_2+k*A_1+A_0)x=0, and their approximations
     37:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     39:   /* A[0] is the 2-D Laplacian */
     40:   PetscCall(MatCreate(PETSC_COMM_WORLD,&A[0]));
     41:   PetscCall(MatSetSizes(A[0],PETSC_DECIDE,PETSC_DECIDE,N,N));
     42:   PetscCall(MatSetFromOptions(A[0]));
     43:   PetscCall(MatCreate(PETSC_COMM_WORLD,&P[0]));
     44:   PetscCall(MatSetSizes(P[0],PETSC_DECIDE,PETSC_DECIDE,N,N));
     45:   PetscCall(MatSetFromOptions(P[0]));

     47:   PetscCall(MatGetOwnershipRange(A[0],&Istart,&Iend));
     48:   for (II=Istart;II<Iend;II++) {
     49:     i = II/n; j = II-i*n;
     50:     if (i>0) PetscCall(MatSetValue(A[0],II,II-n,-1.0,INSERT_VALUES));
     51:     if (i<m-1) PetscCall(MatSetValue(A[0],II,II+n,-1.0,INSERT_VALUES));
     52:     if (j>0) PetscCall(MatSetValue(A[0],II,II-1,-1.0,INSERT_VALUES));
     53:     if (j<n-1) PetscCall(MatSetValue(A[0],II,II+1,-1.0,INSERT_VALUES));
     54:     PetscCall(MatSetValue(A[0],II,II,4.0,INSERT_VALUES));
     55:     if (j>0) PetscCall(MatSetValue(P[0],II,II-1,-1.0,INSERT_VALUES));
     56:     if (j<n-1) PetscCall(MatSetValue(P[0],II,II+1,-1.0,INSERT_VALUES));
     57:     PetscCall(MatSetValue(P[0],II,II,4.0,INSERT_VALUES));
     58:   }
     59:   PetscCall(MatAssemblyBegin(A[0],MAT_FINAL_ASSEMBLY));
     60:   PetscCall(MatAssemblyEnd(A[0],MAT_FINAL_ASSEMBLY));
     61:   PetscCall(MatAssemblyBegin(P[0],MAT_FINAL_ASSEMBLY));
     62:   PetscCall(MatAssemblyEnd(P[0],MAT_FINAL_ASSEMBLY));

     64:   /* A[1] is the 1-D Laplacian on horizontal lines */
     65:   PetscCall(MatCreate(PETSC_COMM_WORLD,&A[1]));
     66:   PetscCall(MatSetSizes(A[1],PETSC_DECIDE,PETSC_DECIDE,N,N));
     67:   PetscCall(MatSetFromOptions(A[1]));
     68:   PetscCall(MatCreate(PETSC_COMM_WORLD,&P[1]));
     69:   PetscCall(MatSetSizes(P[1],PETSC_DECIDE,PETSC_DECIDE,N,N));
     70:   PetscCall(MatSetFromOptions(P[1]));

     72:   PetscCall(MatGetOwnershipRange(A[1],&Istart,&Iend));
     73:   for (II=Istart;II<Iend;II++) {
     74:     i = II/n; j = II-i*n;
     75:     if (j>0) PetscCall(MatSetValue(A[1],II,II-1,-1.0,INSERT_VALUES));
     76:     if (j<n-1) PetscCall(MatSetValue(A[1],II,II+1,-1.0,INSERT_VALUES));
     77:     PetscCall(MatSetValue(A[1],II,II,2.0,INSERT_VALUES));
     78:     PetscCall(MatSetValue(P[1],II,II,2.0,INSERT_VALUES));
     79:   }
     80:   PetscCall(MatAssemblyBegin(A[1],MAT_FINAL_ASSEMBLY));
     81:   PetscCall(MatAssemblyEnd(A[1],MAT_FINAL_ASSEMBLY));
     82:   PetscCall(MatAssemblyBegin(P[1],MAT_FINAL_ASSEMBLY));
     83:   PetscCall(MatAssemblyEnd(P[1],MAT_FINAL_ASSEMBLY));

     85:   /* A[2] is a diagonal matrix */
     86:   PetscCall(MatCreate(PETSC_COMM_WORLD,&A[2]));
     87:   PetscCall(MatSetSizes(A[2],PETSC_DECIDE,PETSC_DECIDE,N,N));
     88:   PetscCall(MatSetFromOptions(A[2]));
     89:   PetscCall(MatCreate(PETSC_COMM_WORLD,&P[2]));
     90:   PetscCall(MatSetSizes(P[2],PETSC_DECIDE,PETSC_DECIDE,N,N));
     91:   PetscCall(MatSetFromOptions(P[2]));

     93:   PetscCall(MatGetOwnershipRange(A[2],&Istart,&Iend));
     94:   for (II=Istart;II<Iend;II++) {
     95:     PetscCall(MatSetValue(A[2],II,II,(PetscReal)(II+1),INSERT_VALUES));
     96:     PetscCall(MatSetValue(P[2],II,II,(PetscReal)(II+1),INSERT_VALUES));
     97:   }
     98:   PetscCall(MatAssemblyBegin(A[2],MAT_FINAL_ASSEMBLY));
     99:   PetscCall(MatAssemblyEnd(A[2],MAT_FINAL_ASSEMBLY));
    100:   PetscCall(MatAssemblyBegin(P[2],MAT_FINAL_ASSEMBLY));
    101:   PetscCall(MatAssemblyEnd(P[2],MAT_FINAL_ASSEMBLY));

    103:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    104:                 Create the eigensolver and set various options
    105:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    107:   PetscCall(PEPCreate(PETSC_COMM_WORLD,&pep));
    108:   PetscCall(PEPSetOperators(pep,3,A));
    109:   PetscCall(PEPSetProblemType(pep,PEP_HERMITIAN));

    111:   PetscCall(PEPGetST(pep,&st));
    112:   PetscCall(STSetType(st,STSINVERT));
    113:   PetscCall(STSetSplitPreconditioner(st,3,P,SUBSET_NONZERO_PATTERN));

    115:   PetscCall(PEPSetTarget(pep,-2.0));
    116:   PetscCall(PEPSetWhichEigenpairs(pep,PEP_TARGET_MAGNITUDE));

    118:   /*
    119:      Set solver parameters at runtime
    120:   */
    121:   PetscCall(PEPSetFromOptions(pep));

    123:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    124:              Solve the eigensystem, display solution and clean up
    125:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    127:   PetscCall(PEPSolve(pep));
    128:   /* show detailed info unless -terse option is given by user */
    129:   PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
    130:   if (terse) PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL));
    131:   else {
    132:     PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
    133:     PetscCall(PEPConvergedReasonView(pep,PETSC_VIEWER_STDOUT_WORLD));
    134:     PetscCall(PEPErrorView(pep,PEP_ERROR_BACKWARD,PETSC_VIEWER_STDOUT_WORLD));
    135:     PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
    136:   }
    137:   PetscCall(PEPDestroy(&pep));
    138:   PetscCall(MatDestroy(&A[0]));
    139:   PetscCall(MatDestroy(&A[1]));
    140:   PetscCall(MatDestroy(&A[2]));
    141:   PetscCall(MatDestroy(&P[0]));
    142:   PetscCall(MatDestroy(&P[1]));
    143:   PetscCall(MatDestroy(&P[2]));
    144:   PetscCall(SlepcFinalize());
    145:   return 0;
    146: }

    148: /*TEST

    150:    testset:
    151:       args: -pep_nev 4 -pep_ncv 28 -n 12 -terse
    152:       output_file: output/ex50_1.out
    153:       requires: double
    154:       test:
    155:          suffix: 1
    156:          args: -pep_type {{toar qarnoldi}}
    157:       test:
    158:          suffix: 1_linear
    159:          args: -pep_type linear -pep_general

    161:    testset:
    162:       args: -pep_all -n 12 -pep_type ciss -rg_type ellipse -rg_ellipse_center -1+1.5i -rg_ellipse_radius .3 -terse
    163:       output_file: output/ex50_2.out
    164:       requires: complex double
    165:       timeoutfactor: 2
    166:       test:
    167:          suffix: 2
    168:       test:
    169:          suffix: 2_par
    170:          nsize: 2
    171:          args: -pep_ciss_partitions 2

    173: TEST*/