Actual source code: test10.c

slepc-3.18.3 2023-03-24
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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:   return 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;

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

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

 46:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 47:      Compute the matrices that define the eigensystem, (k^2*M+k*C+K)x=0
 48:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

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

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

 92:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 93:                 Create the eigensolver and set various options
 94:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

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

107:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
108:                       Solve the eigensystem
109:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

115:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
116:                     Display solution and clean up
117:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

119:   PEPErrorView(pep,PEP_ERROR_BACKWARD,NULL);
120:   PEPDestroy(&pep);
121:   MatDestroy(&M);
122:   MatDestroy(&C);
123:   MatDestroy(&K);
124:   SlepcFinalize();
125:   return 0;
126: }

128: /*TEST

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

134: TEST*/