Actual source code: test7.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[] = "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;
27: SlepcInitialize(&argc,&argv,(char*)0,help);
28: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
29: PetscPrintf(PETSC_COMM_WORLD,"\n1-D Laplacian, n=%" PetscInt_FMT "\n\n",n);
31: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
32: Compute the operator matrix for the 1-D Laplacian
33: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
35: MatCreate(PETSC_COMM_WORLD,&A);
36: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,n,n);
37: MatSetFromOptions(A);
38: MatSetUp(A);
40: MatGetOwnershipRange(A,&Istart,&Iend);
41: for (i=Istart;i<Iend;i++) {
42: if (i>0) MatSetValue(A,i,i-1,-1.0,INSERT_VALUES);
43: if (i<n-1) MatSetValue(A,i,i+1,-1.0,INSERT_VALUES);
44: MatSetValue(A,i,i,2.0,INSERT_VALUES);
45: }
46: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
47: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
48: MatCreateVecs(A,&v,&w);
49: VecSet(v,1.0);
51: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
52: Compute the split preconditioner matrix (one diagonal)
53: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
55: MatCreate(PETSC_COMM_WORLD,&Pa);
56: MatSetSizes(Pa,PETSC_DECIDE,PETSC_DECIDE,n,n);
57: MatSetFromOptions(Pa);
58: MatSetUp(Pa);
60: MatGetOwnershipRange(Pa,&Istart,&Iend);
61: for (i=Istart;i<Iend;i++) MatSetValue(Pa,i,i,2.0,INSERT_VALUES);
62: MatAssemblyBegin(Pa,MAT_FINAL_ASSEMBLY);
63: MatAssemblyEnd(Pa,MAT_FINAL_ASSEMBLY);
65: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
66: Create the spectral transformation object
67: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
69: STCreate(PETSC_COMM_WORLD,&st);
70: mat[0] = A;
71: STSetMatrices(st,1,mat);
72: mat[0] = Pa;
73: STSetSplitPreconditioner(st,1,mat,SAME_NONZERO_PATTERN);
74: STSetTransform(st,PETSC_TRUE);
75: STSetFromOptions(st);
76: STCayleySetAntishift(st,-0.3); /* only relevant for cayley */
78: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
79: Form the preconditioner matrix and print it
80: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
82: PetscObjectTypeCompareAny((PetscObject)st,&flg,STSINVERT,STCAYLEY,"");
83: if (flg) {
84: STGetKSP(st,&ksp);
85: KSPGetPC(ksp,&pc);
86: STGetOperator(st,NULL);
87: PCGetOperators(pc,NULL,&Pmat);
88: MatView(Pmat,NULL);
89: }
91: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
92: Apply the operator
93: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
95: /* sigma=0.0 */
96: STSetUp(st);
97: STGetType(st,&type);
98: PetscPrintf(PETSC_COMM_WORLD,"ST type %s\n",type);
99: STApply(st,v,w);
100: VecView(w,NULL);
102: /* sigma=0.1 */
103: sigma = 0.1;
104: STSetShift(st,sigma);
105: STGetShift(st,&sigma);
106: PetscPrintf(PETSC_COMM_WORLD,"With shift=%g\n",(double)PetscRealPart(sigma));
107: if (flg) {
108: STGetOperator(st,NULL);
109: PCGetOperators(pc,NULL,&Pmat);
110: MatView(Pmat,NULL);
111: }
112: STApply(st,v,w);
113: VecView(w,NULL);
115: STDestroy(&st);
116: MatDestroy(&A);
117: MatDestroy(&Pa);
118: VecDestroy(&v);
119: VecDestroy(&w);
120: SlepcFinalize();
121: return 0;
122: }
124: /*TEST
126: test:
127: suffix: 1
128: args: -st_type {{cayley shift sinvert}separate output}
129: requires: !single
131: TEST*/