Actual source code: test4.c
slepc-3.20.1 2023-11-27
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[] = "Test the solution of a HEP without calling EPSSetFromOptions (based on ex1.c).\n\n"
12: "The command line options are:\n"
13: " -n <n>, where <n> = number of grid subdivisions = matrix dimension.\n"
14: " -type <eps_type> = eps type to test.\n\n";
16: #include <slepceps.h>
18: int main(int argc,char **argv)
19: {
20: Mat A; /* problem matrix */
21: EPS eps; /* eigenproblem solver context */
22: PetscReal tol=1000*PETSC_MACHINE_EPSILON;
23: PetscInt n=30,i,Istart,Iend,nev;
24: PetscBool flg,gd2;
25: char epstype[30] = "krylovschur";
27: PetscFunctionBeginUser;
28: PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));
30: PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
31: PetscCall(PetscOptionsGetString(NULL,NULL,"-type",epstype,sizeof(epstype),NULL));
32: PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\n1-D Laplacian Eigenproblem, n=%" PetscInt_FMT "\n\n",n));
34: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
35: Compute the operator matrix that defines the eigensystem, Ax=kx
36: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
38: PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
39: PetscCall(MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n));
40: PetscCall(MatSetFromOptions(A));
41: PetscCall(MatSetUp(A));
43: PetscCall(MatGetOwnershipRange(A,&Istart,&Iend));
44: for (i=Istart;i<Iend;i++) {
45: if (i>0) PetscCall(MatSetValue(A,i,i-1,-1.0,INSERT_VALUES));
46: if (i<n-1) PetscCall(MatSetValue(A,i,i+1,-1.0,INSERT_VALUES));
47: PetscCall(MatSetValue(A,i,i,2.0,INSERT_VALUES));
48: }
49: PetscCall(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY));
50: PetscCall(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY));
52: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
53: Create the eigensolver and set various options
54: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
55: /*
56: Create eigensolver context
57: */
58: PetscCall(EPSCreate(PETSC_COMM_WORLD,&eps));
60: /*
61: Set operators. In this case, it is a standard eigenvalue problem
62: */
63: PetscCall(EPSSetOperators(eps,A,NULL));
64: PetscCall(EPSSetProblemType(eps,EPS_HEP));
65: PetscCall(EPSSetDimensions(eps,4,PETSC_DEFAULT,PETSC_DEFAULT));
66: PetscCall(EPSSetTolerances(eps,tol,PETSC_DEFAULT));
68: /*
69: Set solver parameters at runtime
70: */
71: PetscCall(PetscStrcmp(epstype,"gd2",&flg));
72: if (flg) {
73: PetscCall(EPSSetType(eps,EPSGD));
74: PetscCall(EPSGDSetDoubleExpansion(eps,PETSC_TRUE));
75: PetscCall(EPSGDGetDoubleExpansion(eps,&gd2)); /* not used */
76: } else PetscCall(EPSSetType(eps,epstype));
77: PetscCall(PetscStrcmp(epstype,"jd",&flg));
78: if (flg) {
79: PetscCall(EPSSetWhichEigenpairs(eps,EPS_TARGET_MAGNITUDE));
80: PetscCall(EPSSetTarget(eps,4.0));
81: }
82: PetscCall(PetscStrcmp(epstype,"lanczos",&flg));
83: if (flg) PetscCall(EPSLanczosSetReorthog(eps,EPS_LANCZOS_REORTHOG_LOCAL));
84: PetscCall(PetscObjectTypeCompareAny((PetscObject)eps,&flg,EPSRQCG,EPSLOBPCG,""));
85: if (flg) PetscCall(EPSSetWhichEigenpairs(eps,EPS_SMALLEST_REAL));
87: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
88: Solve the eigensystem
89: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
91: PetscCall(EPSSolve(eps));
92: PetscCall(EPSGetDimensions(eps,&nev,NULL,NULL));
93: PetscCall(PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %" PetscInt_FMT "\n",nev));
95: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
96: Display solution and clean up
97: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
99: PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
100: PetscCall(EPSDestroy(&eps));
101: PetscCall(MatDestroy(&A));
102: PetscCall(SlepcFinalize());
103: return 0;
104: }
106: /*TEST
108: testset:
109: filter: sed -e "s/3.95905/3.95906/"
110: output_file: output/test4_1.out
111: test:
112: suffix: 1
113: args: -type {{krylovschur subspace arnoldi lanczos gd jd gd2 lapack}}
114: test:
115: suffix: 1_arpack
116: args: -type arpack
117: requires: arpack
118: test:
119: suffix: 1_primme
120: args: -type primme
121: requires: primme
122: test:
123: suffix: 1_trlan
124: args: -type trlan
125: requires: trlan
127: test:
128: suffix: 2
129: args: -type {{rqcg lobpcg}}
131: TEST*/