Actual source code: ex13.c
slepc-3.14.1 2020-12-08
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2020, 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[] = "Generalized Symmetric eigenproblem.\n\n"
12: "The problem is Ax = lambda Bx, with:\n"
13: " A = Laplacian operator in 2-D\n"
14: " B = diagonal matrix with all values equal to 4 except nulldim zeros\n\n"
15: "The command line options are:\n"
16: " -n <n>, where <n> = number of grid subdivisions in x dimension.\n"
17: " -m <m>, where <m> = number of grid subdivisions in y dimension.\n"
18: " -nulldim <k>, where <k> = dimension of the nullspace of B.\n\n";
20: #include <slepceps.h>
22: int main(int argc,char **argv)
23: {
24: Mat A,B; /* matrices */
25: EPS eps; /* eigenproblem solver context */
26: EPSType type;
27: PetscInt N,n=10,m,Istart,Iend,II,nev,i,j,nulldim=0;
28: PetscBool flag,terse;
31: SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
33: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
34: PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag);
35: if (!flag) m=n;
36: N = n*m;
37: PetscOptionsGetInt(NULL,NULL,"-nulldim",&nulldim,NULL);
38: PetscPrintf(PETSC_COMM_WORLD,"\nGeneralized Symmetric Eigenproblem, N=%D (%Dx%D grid), null(B)=%D\n\n",N,n,m,nulldim);
40: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
41: Compute the matrices that define the eigensystem, Ax=kBx
42: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
44: MatCreate(PETSC_COMM_WORLD,&A);
45: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N);
46: MatSetFromOptions(A);
47: MatSetUp(A);
49: MatCreate(PETSC_COMM_WORLD,&B);
50: MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,N,N);
51: MatSetFromOptions(B);
52: MatSetUp(B);
54: MatGetOwnershipRange(A,&Istart,&Iend);
55: for (II=Istart;II<Iend;II++) {
56: i = II/n; j = II-i*n;
57: if (i>0) { MatSetValue(A,II,II-n,-1.0,INSERT_VALUES); }
58: if (i<m-1) { MatSetValue(A,II,II+n,-1.0,INSERT_VALUES); }
59: if (j>0) { MatSetValue(A,II,II-1,-1.0,INSERT_VALUES); }
60: if (j<n-1) { MatSetValue(A,II,II+1,-1.0,INSERT_VALUES); }
61: MatSetValue(A,II,II,4.0,INSERT_VALUES);
62: if (II>=nulldim) { MatSetValue(B,II,II,4.0,INSERT_VALUES); }
63: }
65: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
66: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
67: MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
68: MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);
70: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
71: Create the eigensolver and set various options
72: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
74: /*
75: Create eigensolver context
76: */
77: EPSCreate(PETSC_COMM_WORLD,&eps);
79: /*
80: Set operators. In this case, it is a generalized eigenvalue problem
81: */
82: EPSSetOperators(eps,A,B);
83: EPSSetProblemType(eps,EPS_GHEP);
85: /*
86: Set solver parameters at runtime
87: */
88: EPSSetFromOptions(eps);
90: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
91: Solve the eigensystem
92: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
94: EPSSolve(eps);
96: /*
97: Optional: Get some information from the solver and display it
98: */
99: EPSGetType(eps,&type);
100: PetscPrintf(PETSC_COMM_WORLD," Solution method: %s\n\n",type);
101: EPSGetDimensions(eps,&nev,NULL,NULL);
102: PetscPrintf(PETSC_COMM_WORLD," Number of requested eigenvalues: %D\n",nev);
104: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
105: Display solution and clean up
106: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
108: /* show detailed info unless -terse option is given by user */
109: PetscOptionsHasName(NULL,NULL,"-terse",&terse);
110: if (terse) {
111: EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
112: } else {
113: PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
114: EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD);
115: EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
116: PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
117: }
118: EPSDestroy(&eps);
119: MatDestroy(&A);
120: MatDestroy(&B);
121: SlepcFinalize();
122: return ierr;
123: }
125: /*TEST
127: test:
128: suffix: 1
129: args: -eps_nev 4 -eps_ncv 22 -eps_tol 1e-5 -st_type sinvert -terse
130: filter: grep -v Solution
132: test:
133: suffix: 2
134: args: -n 110 -nulldim 6 -eps_nev 4 -eps_ncv 18 -eps_tol 1e-5 -eps_purify 1 -st_type sinvert -st_matstructure {{different subset}} -terse
135: requires: !single
137: test:
138: suffix: 3
139: args: -eps_nev 3 -eps_tol 1e-5 -mat_type sbaij -st_type sinvert -terse
141: test:
142: suffix: 4
143: args: -eps_nev 4 -eps_tol 1e-5 -eps_smallest_real -eps_type {{gd lobpcg rqcg}} -terse
144: output_file: output/ex13_1.out
145: filter: grep -v Solution
147: test:
148: suffix: 5_primme
149: args: -n 10 -m 12 -eps_nev 4 -eps_target 0.9 -eps_max_it 15000 -eps_type primme -st_pc_type jacobi -terse
150: requires: primme define(SLEPC_HAVE_PRIMME3)
152: TEST*/