Actual source code: pbjacobi.c
1: /*$Id: pbjacobi.c,v 1.4 2001/08/07 03:03:42 balay Exp $*/
3: /*
4: Include files needed for the PBJacobi preconditioner:
5: pcimpl.h - private include file intended for use by all preconditioners
6: */
8: #include src/ksp/pc/pcimpl.h
10: /*
11: Private context (data structure) for the PBJacobi preconditioner.
12: */
13: typedef struct {
14: PetscScalar *diag;
15: int bs,mbs;
16: } PC_PBJacobi;
18: /*
19: Currently only implemented for baij matrices and directly access baij
20: data structures.
21: */
22: #include src/mat/impls/baij/mpi/mpibaij.h
23: #include src/inline/ilu.h
27: static int PCApply_PBJacobi_2(PC pc,Vec x,Vec y)
28: {
29: PC_PBJacobi *jac = (PC_PBJacobi*)pc->data;
30: int ierr,i,m = jac->mbs;
31: PetscScalar *diag = jac->diag,x0,x1,*xx,*yy;
32:
34: VecGetArray(x,&xx);
35: VecGetArray(y,&yy);
36: for (i=0; i<m; i++) {
37: x0 = xx[2*i]; x1 = xx[2*i+1];
38: yy[2*i] = diag[0]*x0 + diag[2]*x1;
39: yy[2*i+1] = diag[1]*x0 + diag[3]*x1;
40: diag += 4;
41: }
42: VecRestoreArray(x,&xx);
43: VecRestoreArray(y,&yy);
44: PetscLogFlops(6*m);
45: return(0);
46: }
49: static int PCApply_PBJacobi_3(PC pc,Vec x,Vec y)
50: {
51: PC_PBJacobi *jac = (PC_PBJacobi*)pc->data;
52: int ierr,i,m = jac->mbs;
53: PetscScalar *diag = jac->diag,x0,x1,x2,*xx,*yy;
54:
56: VecGetArray(x,&xx);
57: VecGetArray(y,&yy);
58: for (i=0; i<m; i++) {
59: x0 = xx[3*i]; x1 = xx[3*i+1]; x2 = xx[3*i+2];
60: yy[3*i] = diag[0]*x0 + diag[3]*x1 + diag[6]*x2;
61: yy[3*i+1] = diag[1]*x0 + diag[4]*x1 + diag[7]*x2;
62: yy[3*i+2] = diag[2]*x0 + diag[5]*x1 + diag[8]*x2;
63: diag += 9;
64: }
65: VecRestoreArray(x,&xx);
66: VecRestoreArray(y,&yy);
67: PetscLogFlops(15*m);
68: return(0);
69: }
72: static int PCApply_PBJacobi_4(PC pc,Vec x,Vec y)
73: {
74: PC_PBJacobi *jac = (PC_PBJacobi*)pc->data;
75: int ierr,i,m = jac->mbs;
76: PetscScalar *diag = jac->diag,x0,x1,x2,x3,*xx,*yy;
77:
79: VecGetArray(x,&xx);
80: VecGetArray(y,&yy);
81: for (i=0; i<m; i++) {
82: x0 = xx[4*i]; x1 = xx[4*i+1]; x2 = xx[4*i+2]; x3 = xx[4*i+3];
83: yy[4*i] = diag[0]*x0 + diag[4]*x1 + diag[8]*x2 + diag[12]*x3;
84: yy[4*i+1] = diag[1]*x0 + diag[5]*x1 + diag[9]*x2 + diag[13]*x3;
85: yy[4*i+2] = diag[2]*x0 + diag[6]*x1 + diag[10]*x2 + diag[14]*x3;
86: yy[4*i+3] = diag[3]*x0 + diag[7]*x1 + diag[11]*x2 + diag[15]*x3;
87: diag += 16;
88: }
89: VecRestoreArray(x,&xx);
90: VecRestoreArray(y,&yy);
91: PetscLogFlops(28*m);
92: return(0);
93: }
96: static int PCApply_PBJacobi_5(PC pc,Vec x,Vec y)
97: {
98: PC_PBJacobi *jac = (PC_PBJacobi*)pc->data;
99: int ierr,i,m = jac->mbs;
100: PetscScalar *diag = jac->diag,x0,x1,x2,x3,x4,*xx,*yy;
101:
103: VecGetArray(x,&xx);
104: VecGetArray(y,&yy);
105: for (i=0; i<m; i++) {
106: x0 = xx[5*i]; x1 = xx[5*i+1]; x2 = xx[5*i+2]; x3 = xx[5*i+3]; x4 = xx[5*i+4];
107: yy[5*i] = diag[0]*x0 + diag[5]*x1 + diag[10]*x2 + diag[15]*x3 + diag[20]*x4;
108: yy[5*i+1] = diag[1]*x0 + diag[6]*x1 + diag[11]*x2 + diag[16]*x3 + diag[21]*x4;
109: yy[5*i+2] = diag[2]*x0 + diag[7]*x1 + diag[12]*x2 + diag[17]*x3 + diag[22]*x4;
110: yy[5*i+3] = diag[3]*x0 + diag[8]*x1 + diag[13]*x2 + diag[18]*x3 + diag[23]*x4;
111: yy[5*i+4] = diag[4]*x0 + diag[9]*x1 + diag[14]*x2 + diag[19]*x3 + diag[24]*x4;
112: diag += 25;
113: }
114: VecRestoreArray(x,&xx);
115: VecRestoreArray(y,&yy);
116: PetscLogFlops(45*m);
117: return(0);
118: }
119: /* -------------------------------------------------------------------------- */
120: extern int MatInvertBlockDiagonal_SeqBAIJ(Mat);
123: static int PCSetUp_PBJacobi(PC pc)
124: {
125: PC_PBJacobi *jac = (PC_PBJacobi*)pc->data;
126: int ierr,size;
127: PetscTruth seqbaij,mpibaij,baij;
128: Mat A = pc->pmat;
129: Mat_SeqBAIJ *a;
132: PetscTypeCompare((PetscObject)pc->pmat,MATSEQBAIJ,&seqbaij);
133: PetscTypeCompare((PetscObject)pc->pmat,MATMPIBAIJ,&mpibaij);
134: PetscTypeCompare((PetscObject)pc->pmat,MATBAIJ,&baij);
135: if (!seqbaij && !mpibaij && !baij) {
136: SETERRQ(1,"Currently only supports BAIJ matrices");
137: }
138: MPI_Comm_size(pc->comm,&size);
139: if (mpibaij || (baij && (size > 1))) A = ((Mat_MPIBAIJ*)A->data)->A;
140: if (A->m != A->n) SETERRQ(1,"Supported only for square matrices and square storage");
142: MatInvertBlockDiagonal_SeqBAIJ(A);
143: a = (Mat_SeqBAIJ*)A->data;
144: jac->diag = a->idiag;
145: jac->bs = a->bs;
146: jac->mbs = a->mbs;
147: switch (a->bs){
148: case 2:
149: pc->ops->apply = PCApply_PBJacobi_2;
150: break;
151: case 3:
152: pc->ops->apply = PCApply_PBJacobi_3;
153: break;
154: case 4:
155: pc->ops->apply = PCApply_PBJacobi_4;
156: break;
157: case 5:
158: pc->ops->apply = PCApply_PBJacobi_5;
159: break;
160: default:
161: SETERRQ1(1,"not supported for block size %d",a->bs);
162: }
164: return(0);
165: }
166: /* -------------------------------------------------------------------------- */
169: static int PCDestroy_PBJacobi(PC pc)
170: {
171: PC_PBJacobi *jac = (PC_PBJacobi*)pc->data;
172: int ierr;
175: /*
176: Free the private data structure that was hanging off the PC
177: */
178: PetscFree(jac);
179: return(0);
180: }
181: /* -------------------------------------------------------------------------- */
182: /*MC
183: PCPBJACOBI - Point block Jacobi
185: Level: beginner
187: Concepts: point block Jacobi
189: Notes: Only implemented for the BAIJ matrix formats.
191: .seealso: PCCreate(), PCSetType(), PCType (for list of available types), PC
193: M*/
195: EXTERN_C_BEGIN
198: int PCCreate_PBJacobi(PC pc)
199: {
200: PC_PBJacobi *jac;
201: int ierr;
205: /*
206: Creates the private data structure for this preconditioner and
207: attach it to the PC object.
208: */
209: PetscNew(PC_PBJacobi,&jac);
210: pc->data = (void*)jac;
212: /*
213: Logs the memory usage; this is not needed but allows PETSc to
214: monitor how much memory is being used for various purposes.
215: */
216: PetscLogObjectMemory(pc,sizeof(PC_PBJacobi));
218: /*
219: Initialize the pointers to vectors to ZERO; these will be used to store
220: diagonal entries of the matrix for fast preconditioner application.
221: */
222: jac->diag = 0;
224: /*
225: Set the pointers for the functions that are provided above.
226: Now when the user-level routines (such as PCApply(), PCDestroy(), etc.)
227: are called, they will automatically call these functions. Note we
228: choose not to provide a couple of these functions since they are
229: not needed.
230: */
231: pc->ops->apply = 0; /*set depending on the block size */
232: pc->ops->applytranspose = 0;
233: pc->ops->setup = PCSetUp_PBJacobi;
234: pc->ops->destroy = PCDestroy_PBJacobi;
235: pc->ops->setfromoptions = 0;
236: pc->ops->view = 0;
237: pc->ops->applyrichardson = 0;
238: pc->ops->applysymmetricleft = 0;
239: pc->ops->applysymmetricright = 0;
240: return(0);
241: }
242: EXTERN_C_END