Actual source code: test39.c

slepc-3.20.1 2023-11-27
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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[] = "Tests multiple calls to EPSSolve with matrices of different local size.\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: /*
 19:    Create 2-D Laplacian matrix
 20: */
 21: PetscErrorCode Laplacian(MPI_Comm comm,PetscInt n,PetscInt m,PetscInt shift,Mat *A)
 22: {
 23:   PetscInt       N = n*m,i,j,II,Istart,Iend,nloc;
 24:   PetscMPIInt    rank;

 26:   PetscFunctionBeginUser;
 27:   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank));
 28:   nloc = PETSC_DECIDE;
 29:   PetscCall(PetscSplitOwnership(comm,&nloc,&N));
 30:   if (rank==0) nloc += shift;
 31:   else if (rank==1) nloc -= shift;

 33:   PetscCall(MatCreate(comm,A));
 34:   PetscCall(MatSetSizes(*A,nloc,nloc,N,N));
 35:   PetscCall(MatSetFromOptions(*A));
 36:   PetscCall(MatSetUp(*A));
 37:   PetscCall(MatGetOwnershipRange(*A,&Istart,&Iend));
 38:   for (II=Istart;II<Iend;II++) {
 39:     i = II/n; j = II-i*n;
 40:     if (i>0) PetscCall(MatSetValue(*A,II,II-n,-1.0,INSERT_VALUES));
 41:     if (i<m-1) PetscCall(MatSetValue(*A,II,II+n,-1.0,INSERT_VALUES));
 42:     if (j>0) PetscCall(MatSetValue(*A,II,II-1,-1.0,INSERT_VALUES));
 43:     if (j<n-1) PetscCall(MatSetValue(*A,II,II+1,-1.0,INSERT_VALUES));
 44:     PetscCall(MatSetValue(*A,II,II,4.0,INSERT_VALUES));
 45:   }
 46:   PetscCall(MatAssemblyBegin(*A,MAT_FINAL_ASSEMBLY));
 47:   PetscCall(MatAssemblyEnd(*A,MAT_FINAL_ASSEMBLY));
 48:   PetscFunctionReturn(PETSC_SUCCESS);
 49: }

 51: int main(int argc,char **argv)
 52: {
 53:   Mat            A,B;
 54:   EPS            eps;
 55:   PetscInt       N,n=10,m=11,nev=3;
 56:   PetscMPIInt    size;
 57:   PetscBool      flag,terse;

 59:   PetscFunctionBeginUser;
 60:   PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));
 61:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size));
 62:   PetscCheck(size>1,PETSC_COMM_WORLD,PETSC_ERR_WRONG_MPI_SIZE,"This example requires at least two processes");
 63:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
 64:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag));
 65:   N = n*m;
 66:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\n2-D Laplacian Eigenproblem, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m));

 68:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 69:                 Create 2-D Laplacian matrices
 70:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 72:   PetscCall(Laplacian(PETSC_COMM_WORLD,n,m,1,&A));
 73:   PetscCall(Laplacian(PETSC_COMM_WORLD,n,m,-1,&B));

 75:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 76:         Create the eigensolver, set options and solve the eigensystem
 77:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 79:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"First solve:\n\n"));
 80:   PetscCall(EPSCreate(PETSC_COMM_WORLD,&eps));
 81:   PetscCall(EPSSetOperators(eps,A,NULL));
 82:   PetscCall(EPSSetProblemType(eps,EPS_HEP));
 83:   PetscCall(EPSSetWhichEigenpairs(eps,EPS_SMALLEST_REAL));
 84:   PetscCall(EPSSetDimensions(eps,nev,PETSC_DEFAULT,PETSC_DEFAULT));
 85:   PetscCall(EPSSetFromOptions(eps));

 87:   PetscCall(EPSSolve(eps));

 89:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 90:                     Display solution of first solve
 91:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 93:   PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
 94:   if (terse) PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
 95:   else {
 96:     PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
 97:     PetscCall(EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD));
 98:     PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD));
 99:     PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
100:   }

102:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
103:                        Solve with second matrix
104:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

106:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nSecond solve:\n\n"));
107:   /* PetscCall(EPSReset(eps)); */  /* not required, will be called in EPSSetOperators() */
108:   PetscCall(EPSSetOperators(eps,B,NULL));
109:   PetscCall(EPSSolve(eps));

111:   if (terse) PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
112:   else {
113:     PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
114:     PetscCall(EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD));
115:     PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD));
116:     PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
117:   }

119:   PetscCall(EPSDestroy(&eps));
120:   PetscCall(MatDestroy(&A));
121:   PetscCall(MatDestroy(&B));
122:   PetscCall(SlepcFinalize());
123:   return 0;
124: }

126: /*TEST

128:    testset:
129:       nsize: 2
130:       requires: !single
131:       output_file: output/test39_1.out
132:       test:
133:          suffix: 1
134:          args: -eps_type {{krylovschur arnoldi lobpcg lapack}} -terse
135:       test:
136:          suffix: 1_lanczos
137:          args: -eps_type lanczos -eps_lanczos_reorthog local -terse

139: TEST*/