Actual source code: test39.c

slepc-3.15.1 2021-05-28
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2021, 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: {
 24:   PetscInt       N = n*m,i,j,II,Istart,Iend,nloc;
 25:   PetscMPIInt    rank;

 28:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRMPI(ierr);
 29:   nloc = PETSC_DECIDE;
 30:   PetscSplitOwnership(comm,&nloc,&N);
 31:   if (rank==0) nloc += shift;
 32:   else if (rank==1) nloc -= shift;

 34:   MatCreate(comm,A);
 35:   MatSetSizes(*A,nloc,nloc,N,N);
 36:   MatSetFromOptions(*A);
 37:   MatSetUp(*A);
 38:   MatGetOwnershipRange(*A,&Istart,&Iend);
 39:   for (II=Istart;II<Iend;II++) {
 40:     i = II/n; j = II-i*n;
 41:     if (i>0) { MatSetValue(*A,II,II-n,-1.0,INSERT_VALUES); }
 42:     if (i<m-1) { MatSetValue(*A,II,II+n,-1.0,INSERT_VALUES); }
 43:     if (j>0) { MatSetValue(*A,II,II-1,-1.0,INSERT_VALUES); }
 44:     if (j<n-1) { MatSetValue(*A,II,II+1,-1.0,INSERT_VALUES); }
 45:     MatSetValue(*A,II,II,4.0,INSERT_VALUES);
 46:   }
 47:   MatAssemblyBegin(*A,MAT_FINAL_ASSEMBLY);
 48:   MatAssemblyEnd(*A,MAT_FINAL_ASSEMBLY);
 49:   return(0);
 50: }

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

 61:   SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
 62:   MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRMPI(ierr);
 63:   if (size==1) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_WRONG_MPI_SIZE,"This example requires at least two processes");
 64:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 65:   PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag);
 66:   N = n*m;
 67:   PetscPrintf(PETSC_COMM_WORLD,"\n2-D Laplacian Eigenproblem, N=%D (%Dx%D grid)\n\n",N,n,m);

 69:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 70:                 Create 2-D Laplacian matrices
 71:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

 76:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 77:         Create the eigensolver, set options and solve the eigensystem
 78:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

 88:   EPSSolve(eps);

 90:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 91:                     Display solution of first solve
 92:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 94:   PetscOptionsHasName(NULL,NULL,"-terse",&terse);
 95:   if (terse) {
 96:     EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
 97:   } else {
 98:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
 99:     EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD);
100:     EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
101:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
102:   }

104:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
105:                        Solve with second matrix
106:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

113:   if (terse) {
114:     EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
115:   } else {
116:     PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
117:     EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD);
118:     EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
119:     PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
120:   }

122:   EPSDestroy(&eps);
123:   MatDestroy(&A);
124:   MatDestroy(&B);
125:   SlepcFinalize();
126:   return ierr;
127: }

129: /*TEST

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

142: TEST*/