Actual source code: test4.c
slepc-3.18.0 2022-10-01
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";
28: SlepcInitialize(&argc,&argv,(char*)0,help);
30: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
31: PetscOptionsGetString(NULL,NULL,"-type",epstype,sizeof(epstype),NULL);
32: 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: MatCreate(PETSC_COMM_WORLD,&A);
39: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
40: MatSetFromOptions(A);
41: MatSetUp(A);
43: MatGetOwnershipRange(A,&Istart,&Iend);
44: for (i=Istart;i<Iend;i++) {
45: if (i>0) MatSetValue(A,i,i-1,-1.0,INSERT_VALUES);
46: if (i<n-1) MatSetValue(A,i,i+1,-1.0,INSERT_VALUES);
47: MatSetValue(A,i,i,2.0,INSERT_VALUES);
48: }
49: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
50: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
52: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
53: Create the eigensolver and set various options
54: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
55: /*
56: Create eigensolver context
57: */
58: EPSCreate(PETSC_COMM_WORLD,&eps);
60: /*
61: Set operators. In this case, it is a standard eigenvalue problem
62: */
63: EPSSetOperators(eps,A,NULL);
64: EPSSetProblemType(eps,EPS_HEP);
65: EPSSetDimensions(eps,4,PETSC_DEFAULT,PETSC_DEFAULT);
66: EPSSetTolerances(eps,tol,PETSC_DEFAULT);
68: /*
69: Set solver parameters at runtime
70: */
71: PetscStrcmp(epstype,"gd2",&flg);
72: if (flg) {
73: EPSSetType(eps,EPSGD);
74: EPSGDSetDoubleExpansion(eps,PETSC_TRUE);
75: EPSGDGetDoubleExpansion(eps,&gd2); /* not used */
76: } else EPSSetType(eps,epstype);
77: PetscStrcmp(epstype,"jd",&flg);
78: if (flg) {
79: EPSSetWhichEigenpairs(eps,EPS_TARGET_MAGNITUDE);
80: EPSSetTarget(eps,4.0);
81: }
82: PetscStrcmp(epstype,"lanczos",&flg);
83: if (flg) EPSLanczosSetReorthog(eps,EPS_LANCZOS_REORTHOG_LOCAL);
84: PetscObjectTypeCompareAny((PetscObject)eps,&flg,EPSRQCG,EPSLOBPCG,"");
85: if (flg) EPSSetWhichEigenpairs(eps,EPS_SMALLEST_REAL);
87: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
88: Solve the eigensystem
89: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
91: EPSSolve(eps);
92: EPSGetDimensions(eps,&nev,NULL,NULL);
93: PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %" PetscInt_FMT "\n",nev);
95: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
96: Display solution and clean up
97: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
99: EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
100: EPSDestroy(&eps);
101: MatDestroy(&A);
102: SlepcFinalize();
103: return 0;
104: }
106: /*TEST
108: testset:
109: output_file: output/test4_1.out
110: test:
111: suffix: 1
112: args: -type {{krylovschur subspace arnoldi lanczos gd jd gd2 lapack}}
113: test:
114: suffix: 1_arpack
115: args: -type arpack
116: requires: arpack
117: test:
118: suffix: 1_primme
119: args: -type primme
120: requires: primme
121: test:
122: suffix: 1_trlan
123: args: -type trlan
124: requires: trlan
126: test:
127: suffix: 2
128: args: -type {{rqcg lobpcg}}
130: TEST*/