Actual source code: ex49.c
slepc-3.17.2 2022-08-09
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[] = "User-defined split preconditioner when solving a generalized eigenproblem.\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 <slepceps.h>
18: int main(int argc,char **argv)
19: {
20: Mat A,B,A0,B0,mats[2]; /* problem matrices and sparser approximations */
21: EPS eps; /* eigenproblem solver context */
22: ST st;
23: PetscInt N,n=24,m,Istart,Iend,II,i,j;
24: PetscBool flag,terse;
26: SlepcInitialize(&argc,&argv,(char*)0,help);
28: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
29: PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag);
30: if (!flag) m=n;
31: N = n*m;
32: PetscPrintf(PETSC_COMM_WORLD,"\nGHEP with split preconditioner, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m);
34: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
35: Compute the problem matrices A and B
36: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
38: MatCreate(PETSC_COMM_WORLD,&A);
39: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N);
40: MatSetFromOptions(A);
41: MatSetUp(A);
43: MatCreate(PETSC_COMM_WORLD,&B);
44: MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,N,N);
45: MatSetFromOptions(B);
46: MatSetUp(B);
48: MatGetOwnershipRange(A,&Istart,&Iend);
49: for (II=Istart;II<Iend;II++) {
50: i = II/n; j = II-i*n;
51: if (i>0) MatSetValue(A,II,II-n,-0.2,INSERT_VALUES);
52: if (i<m-1) MatSetValue(A,II,II+n,-0.2,INSERT_VALUES);
53: if (j>0) MatSetValue(A,II,II-1,-3.0,INSERT_VALUES);
54: if (j<n-1) MatSetValue(A,II,II+1,-3.0,INSERT_VALUES);
55: MatSetValue(A,II,II,7.0,INSERT_VALUES);
56: MatSetValue(B,II,II,2.0,INSERT_VALUES);
57: }
58: if (Istart==0) {
59: MatSetValue(B,0,0,6.0,INSERT_VALUES);
60: MatSetValue(B,0,1,-1.0,INSERT_VALUES);
61: MatSetValue(B,1,0,-1.0,INSERT_VALUES);
62: MatSetValue(B,1,1,1.0,INSERT_VALUES);
63: }
64: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
65: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
66: MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
67: MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);
69: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
70: Compute sparser approximations A0 and B0
71: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
73: MatCreate(PETSC_COMM_WORLD,&A0);
74: MatSetSizes(A0,PETSC_DECIDE,PETSC_DECIDE,N,N);
75: MatSetFromOptions(A0);
76: MatSetUp(A0);
78: MatCreate(PETSC_COMM_WORLD,&B0);
79: MatSetSizes(B0,PETSC_DECIDE,PETSC_DECIDE,N,N);
80: MatSetFromOptions(B0);
81: MatSetUp(B0);
83: MatGetOwnershipRange(A0,&Istart,&Iend);
84: for (II=Istart;II<Iend;II++) {
85: i = II/n; j = II-i*n;
86: if (j>0) MatSetValue(A0,II,II-1,-3.0,INSERT_VALUES);
87: if (j<n-1) MatSetValue(A0,II,II+1,-3.0,INSERT_VALUES);
88: MatSetValue(A0,II,II,7.0,INSERT_VALUES);
89: MatSetValue(B0,II,II,2.0,INSERT_VALUES);
90: }
91: if (Istart==0) {
92: MatSetValue(B0,0,0,6.0,INSERT_VALUES);
93: MatSetValue(B0,1,1,1.0,INSERT_VALUES);
94: }
95: MatAssemblyBegin(A0,MAT_FINAL_ASSEMBLY);
96: MatAssemblyEnd(A0,MAT_FINAL_ASSEMBLY);
97: MatAssemblyBegin(B0,MAT_FINAL_ASSEMBLY);
98: MatAssemblyEnd(B0,MAT_FINAL_ASSEMBLY);
100: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
101: Create the eigensolver and set various options
102: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
104: EPSCreate(PETSC_COMM_WORLD,&eps);
105: EPSSetOperators(eps,A,B);
106: EPSSetProblemType(eps,EPS_GHEP);
107: EPSGetST(eps,&st);
108: STSetType(st,STSINVERT);
109: mats[0] = A0; mats[1] = B0;
110: STSetSplitPreconditioner(st,2,mats,SUBSET_NONZERO_PATTERN);
111: EPSSetTarget(eps,0.0);
112: EPSSetWhichEigenpairs(eps,EPS_TARGET_MAGNITUDE);
113: EPSSetFromOptions(eps);
115: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
116: Solve the eigensystem and display solution
117: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
119: EPSSolve(eps);
121: /* show detailed info unless -terse option is given by user */
122: PetscOptionsHasName(NULL,NULL,"-terse",&terse);
123: if (terse) EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL);
124: else {
125: PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL);
126: EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD);
127: EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD);
128: PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD);
129: }
130: EPSDestroy(&eps);
131: MatDestroy(&A);
132: MatDestroy(&B);
133: MatDestroy(&A0);
134: MatDestroy(&B0);
135: SlepcFinalize();
136: return 0;
137: }
139: /*TEST
141: testset:
142: args: -eps_nev 4 -terse
143: output_file: output/ex49_1.out
144: requires: !single
145: test:
146: suffix: 1
147: test:
148: suffix: 1_jd
149: args: -eps_type jd -st_type precond
150: test:
151: suffix: 1_lobpcg
152: args: -eps_type lobpcg -st_type precond -eps_smallest_real -st_shift 0.2
154: testset:
155: args: -eps_type ciss -eps_all -rg_type ellipse -rg_ellipse_center 0 -rg_ellipse_radius 0.34 -rg_ellipse_vscale .2 -terse
156: output_file: output/ex49_2.out
157: test:
158: suffix: 2
159: test:
160: suffix: 2_nost
161: args: -eps_ciss_usest 0
162: requires: !single
163: test:
164: suffix: 2_par
165: nsize: 2
166: args: -eps_ciss_partitions 2
167: requires: !single
169: TEST*/