Actual source code: test8.c
slepc-3.18.1 2022-11-02
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 ST with two matrices and split preconditioner.\n\n";
13: #include <slepcst.h>
15: int main(int argc,char **argv)
16: {
17: Mat A,B,Pa,Pb,Pmat,mat[2];
18: ST st;
19: KSP ksp;
20: PC pc;
21: Vec v,w;
22: STType type;
23: PetscScalar sigma;
24: PetscInt n=10,i,Istart,Iend;
27: SlepcInitialize(&argc,&argv,(char*)0,help);
28: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
29: PetscPrintf(PETSC_COMM_WORLD,"\n1-D Laplacian plus diagonal, n=%" PetscInt_FMT "\n\n",n);
31: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
32: Compute the operator matrices (1-D Laplacian and diagonal)
33: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
35: MatCreate(PETSC_COMM_WORLD,&A);
36: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
37: MatSetFromOptions(A);
38: MatSetUp(A);
40: MatCreate(PETSC_COMM_WORLD,&B);
41: MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,n,n);
42: MatSetFromOptions(B);
43: MatSetUp(B);
45: MatGetOwnershipRange(A,&Istart,&Iend);
46: for (i=Istart;i<Iend;i++) {
47: MatSetValue(A,i,i,2.0,INSERT_VALUES);
48: if (i>0) {
49: MatSetValue(A,i,i-1,-1.0,INSERT_VALUES);
50: MatSetValue(B,i,i,(PetscScalar)i,INSERT_VALUES);
51: } else MatSetValue(B,i,i,-1.0,INSERT_VALUES);
52: if (i<n-1) MatSetValue(A,i,i+1,-1.0,INSERT_VALUES);
53: }
54: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
55: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
56: MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
57: MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);
58: MatCreateVecs(A,&v,&w);
59: VecSet(v,1.0);
61: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
62: Compute the split preconditioner matrices (two diagonals)
63: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
65: MatCreate(PETSC_COMM_WORLD,&Pa);
66: MatSetSizes(Pa,PETSC_DECIDE,PETSC_DECIDE,n,n);
67: MatSetFromOptions(Pa);
68: MatSetUp(Pa);
70: MatCreate(PETSC_COMM_WORLD,&Pb);
71: MatSetSizes(Pb,PETSC_DECIDE,PETSC_DECIDE,n,n);
72: MatSetFromOptions(Pb);
73: MatSetUp(Pb);
75: MatGetOwnershipRange(Pa,&Istart,&Iend);
76: for (i=Istart;i<Iend;i++) {
77: MatSetValue(Pa,i,i,2.0,INSERT_VALUES);
78: if (i>0) MatSetValue(Pb,i,i,(PetscScalar)i,INSERT_VALUES);
79: else MatSetValue(Pb,i,i,-1.0,INSERT_VALUES);
80: }
81: MatAssemblyBegin(Pa,MAT_FINAL_ASSEMBLY);
82: MatAssemblyEnd(Pa,MAT_FINAL_ASSEMBLY);
83: MatAssemblyBegin(Pb,MAT_FINAL_ASSEMBLY);
84: MatAssemblyEnd(Pb,MAT_FINAL_ASSEMBLY);
86: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
87: Create the spectral transformation object
88: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
90: STCreate(PETSC_COMM_WORLD,&st);
91: mat[0] = A;
92: mat[1] = B;
93: STSetMatrices(st,2,mat);
94: mat[0] = Pa;
95: mat[1] = Pb;
96: STSetSplitPreconditioner(st,2,mat,SAME_NONZERO_PATTERN);
97: STSetTransform(st,PETSC_TRUE);
98: STSetFromOptions(st);
99: STCayleySetAntishift(st,-0.2); /* only relevant for cayley */
101: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
102: Form the preconditioner matrix and print it
103: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
105: STGetKSP(st,&ksp);
106: KSPGetPC(ksp,&pc);
107: STGetOperator(st,NULL);
108: PCGetOperators(pc,NULL,&Pmat);
109: MatView(Pmat,NULL);
111: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
112: Apply the operator
113: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
115: /* sigma=0.0 */
116: STSetUp(st);
117: STGetType(st,&type);
118: PetscPrintf(PETSC_COMM_WORLD,"ST type %s\n",type);
119: STApply(st,v,w);
120: VecView(w,NULL);
122: /* sigma=0.1 */
123: sigma = 0.1;
124: STSetShift(st,sigma);
125: STGetShift(st,&sigma);
126: PetscPrintf(PETSC_COMM_WORLD,"With shift=%g\n",(double)PetscRealPart(sigma));
127: STGetOperator(st,NULL);
128: PCGetOperators(pc,NULL,&Pmat);
129: MatView(Pmat,NULL);
130: STApply(st,v,w);
131: VecView(w,NULL);
133: STDestroy(&st);
134: MatDestroy(&A);
135: MatDestroy(&B);
136: MatDestroy(&Pa);
137: MatDestroy(&Pb);
138: VecDestroy(&v);
139: VecDestroy(&w);
140: SlepcFinalize();
141: return 0;
142: }
144: /*TEST
146: test:
147: suffix: 1
148: args: -st_type {{cayley shift sinvert}separate output}
149: requires: !single
151: TEST*/