Actual source code: test7.c
slepc-3.18.2 2023-01-26
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 one matrix and split preconditioner.\n\n";
13: #include <slepcst.h>
15: int main(int argc,char **argv)
16: {
17: Mat A,Pa,Pmat,mat[1];
18: ST st;
19: KSP ksp;
20: PC pc;
21: Vec v,w;
22: STType type;
23: PetscBool flg;
24: PetscScalar sigma;
25: PetscInt n=10,i,Istart,Iend;
28: SlepcInitialize(&argc,&argv,(char*)0,help);
29: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
30: PetscPrintf(PETSC_COMM_WORLD,"\n1-D Laplacian, n=%" PetscInt_FMT "\n\n",n);
32: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
33: Compute the operator matrix for the 1-D Laplacian
34: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
36: MatCreate(PETSC_COMM_WORLD,&A);
37: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
38: MatSetFromOptions(A);
39: MatSetUp(A);
41: MatGetOwnershipRange(A,&Istart,&Iend);
42: for (i=Istart;i<Iend;i++) {
43: if (i>0) MatSetValue(A,i,i-1,-1.0,INSERT_VALUES);
44: if (i<n-1) MatSetValue(A,i,i+1,-1.0,INSERT_VALUES);
45: MatSetValue(A,i,i,2.0,INSERT_VALUES);
46: }
47: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
48: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
49: MatCreateVecs(A,&v,&w);
50: VecSet(v,1.0);
52: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
53: Compute the split preconditioner matrix (one diagonal)
54: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
56: MatCreate(PETSC_COMM_WORLD,&Pa);
57: MatSetSizes(Pa,PETSC_DECIDE,PETSC_DECIDE,n,n);
58: MatSetFromOptions(Pa);
59: MatSetUp(Pa);
61: MatGetOwnershipRange(Pa,&Istart,&Iend);
62: for (i=Istart;i<Iend;i++) MatSetValue(Pa,i,i,2.0,INSERT_VALUES);
63: MatAssemblyBegin(Pa,MAT_FINAL_ASSEMBLY);
64: MatAssemblyEnd(Pa,MAT_FINAL_ASSEMBLY);
66: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
67: Create the spectral transformation object
68: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
70: STCreate(PETSC_COMM_WORLD,&st);
71: mat[0] = A;
72: STSetMatrices(st,1,mat);
73: mat[0] = Pa;
74: STSetSplitPreconditioner(st,1,mat,SAME_NONZERO_PATTERN);
75: STSetTransform(st,PETSC_TRUE);
76: STSetFromOptions(st);
77: STCayleySetAntishift(st,-0.3); /* only relevant for cayley */
79: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
80: Form the preconditioner matrix and print it
81: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
83: PetscObjectTypeCompareAny((PetscObject)st,&flg,STSINVERT,STCAYLEY,"");
84: if (flg) {
85: STGetKSP(st,&ksp);
86: KSPGetPC(ksp,&pc);
87: STGetOperator(st,NULL);
88: PCGetOperators(pc,NULL,&Pmat);
89: MatView(Pmat,NULL);
90: }
92: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
93: Apply the operator
94: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
96: /* sigma=0.0 */
97: STSetUp(st);
98: STGetType(st,&type);
99: PetscPrintf(PETSC_COMM_WORLD,"ST type %s\n",type);
100: STApply(st,v,w);
101: VecView(w,NULL);
103: /* sigma=0.1 */
104: sigma = 0.1;
105: STSetShift(st,sigma);
106: STGetShift(st,&sigma);
107: PetscPrintf(PETSC_COMM_WORLD,"With shift=%g\n",(double)PetscRealPart(sigma));
108: if (flg) {
109: STGetOperator(st,NULL);
110: PCGetOperators(pc,NULL,&Pmat);
111: MatView(Pmat,NULL);
112: }
113: STApply(st,v,w);
114: VecView(w,NULL);
116: STDestroy(&st);
117: MatDestroy(&A);
118: MatDestroy(&Pa);
119: VecDestroy(&v);
120: VecDestroy(&w);
121: SlepcFinalize();
122: return 0;
123: }
125: /*TEST
127: test:
128: suffix: 1
129: args: -st_type {{cayley shift sinvert}separate output}
130: requires: !single
132: TEST*/