Actual source code: test10.c

slepc-3.17.1 2022-04-11
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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 a user-defined convergence test in PEP (based on ex16.c).\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: /*
 19:   MyConvergedRel - Convergence test relative to the norm of M (given in ctx).
 20: */
 21: PetscErrorCode MyConvergedRel(PEP pep,PetscScalar eigr,PetscScalar eigi,PetscReal res,PetscReal *errest,void *ctx)
 22: {
 23:   PetscReal norm = *(PetscReal*)ctx;

 25:   *errest = res/norm;
 26:   PetscFunctionReturn(0);
 27: }

 29: int main(int argc,char **argv)
 30: {
 31:   Mat            M,C,K,A[3];      /* problem matrices */
 32:   PEP            pep;             /* polynomial eigenproblem solver context */
 33:   PetscInt       N,n=10,m,Istart,Iend,II,nev,i,j;
 34:   PetscBool      flag;
 35:   PetscReal      norm;

 37:   SlepcInitialize(&argc,&argv,(char*)0,help);

 39:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 40:   PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag);
 41:   if (!flag) m=n;
 42:   N = n*m;
 43:   PetscPrintf(PETSC_COMM_WORLD,"\nQuadratic Eigenproblem, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m);

 45:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 46:      Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
 47:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 49:   /* K is the 2-D Laplacian */
 50:   MatCreate(PETSC_COMM_WORLD,&K);
 51:   MatSetSizes(K,PETSC_DECIDE,PETSC_DECIDE,N,N);
 52:   MatSetFromOptions(K);
 53:   MatSetUp(K);
 54:   MatGetOwnershipRange(K,&Istart,&Iend);
 55:   for (II=Istart;II<Iend;II++) {
 56:     i = II/n; j = II-i*n;
 57:     if (i>0) MatSetValue(K,II,II-n,-1.0,INSERT_VALUES);
 58:     if (i<m-1) MatSetValue(K,II,II+n,-1.0,INSERT_VALUES);
 59:     if (j>0) MatSetValue(K,II,II-1,-1.0,INSERT_VALUES);
 60:     if (j<n-1) MatSetValue(K,II,II+1,-1.0,INSERT_VALUES);
 61:     MatSetValue(K,II,II,4.0,INSERT_VALUES);
 62:   }
 63:   MatAssemblyBegin(K,MAT_FINAL_ASSEMBLY);
 64:   MatAssemblyEnd(K,MAT_FINAL_ASSEMBLY);

 66:   /* C is the 1-D Laplacian on horizontal lines */
 67:   MatCreate(PETSC_COMM_WORLD,&C);
 68:   MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,N,N);
 69:   MatSetFromOptions(C);
 70:   MatSetUp(C);
 71:   MatGetOwnershipRange(C,&Istart,&Iend);
 72:   for (II=Istart;II<Iend;II++) {
 73:     i = II/n; j = II-i*n;
 74:     if (j>0) MatSetValue(C,II,II-1,-1.0,INSERT_VALUES);
 75:     if (j<n-1) MatSetValue(C,II,II+1,-1.0,INSERT_VALUES);
 76:     MatSetValue(C,II,II,2.0,INSERT_VALUES);
 77:   }
 78:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
 79:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

 81:   /* M is a diagonal matrix */
 82:   MatCreate(PETSC_COMM_WORLD,&M);
 83:   MatSetSizes(M,PETSC_DECIDE,PETSC_DECIDE,N,N);
 84:   MatSetFromOptions(M);
 85:   MatSetUp(M);
 86:   MatGetOwnershipRange(M,&Istart,&Iend);
 87:   for (II=Istart;II<Iend;II++) MatSetValue(M,II,II,(PetscReal)(II+1),INSERT_VALUES);
 88:   MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
 89:   MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);

 91:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 92:                 Create the eigensolver and set various options
 93:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 95:   PEPCreate(PETSC_COMM_WORLD,&pep);
 96:   A[0] = K; A[1] = C; A[2] = M;
 97:   PEPSetOperators(pep,3,A);
 98:   PEPSetProblemType(pep,PEP_HERMITIAN);
 99:   PEPSetDimensions(pep,4,20,PETSC_DEFAULT);

101:   /* setup convergence test relative to the norm of M */
102:   MatNorm(M,NORM_1,&norm);
103:   PEPSetConvergenceTestFunction(pep,MyConvergedRel,&norm,NULL);
104:   PEPSetFromOptions(pep);

106:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
107:                       Solve the eigensystem
108:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

110:   PEPSolve(pep);
111:   PEPGetDimensions(pep,&nev,NULL,NULL);
112:   PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %" PetscInt_FMT "\n",nev);

114:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
115:                     Display solution and clean up
116:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

118:   PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
119:   PEPDestroy(&pep);
120:   MatDestroy(&M);
121:   MatDestroy(&C);
122:   MatDestroy(&K);
123:   SlepcFinalize();
124:   return 0;
125: }

127: /*TEST

129:    testset:
130:       requires: double
131:       suffix: 1

133: TEST*/