Actual source code: ex10.c
2: static char help[] = "Solve a small system and a large system through preloading\n\
3: Input arguments are:\n\
4: -permute <natural,rcm,nd,...> : solve system in permuted indexing\n\
5: -f0 <small_sys_binary> -f1 <large_sys_binary> \n\n";
7: /*
8: Include "petscksp.h" so that we can use KSP solvers. Note that this file
9: automatically includes:
10: petscsys.h - base PETSc routines petscvec.h - vectors
11: petscmat.h - matrices
12: petscis.h - index sets petscksp.h - Krylov subspace methods
13: petscviewer.h - viewers petscpc.h - preconditioners
14: */
15: #include <petscksp.h>
17: typedef enum {
18: RHS_FILE,
19: RHS_ONE,
20: RHS_RANDOM
21: } RHSType;
22: const char *const RHSTypes[] = {"FILE", "ONE", "RANDOM", "RHSType", "RHS_", NULL};
24: PetscErrorCode CheckResult(KSP *ksp, Mat *A, Vec *b, Vec *x, IS *rowperm)
25: {
26: PetscReal norm; /* norm of solution error */
27: PetscInt its;
28: KSPGetTotalIterations(*ksp,&its);
29: PetscPrintf(PETSC_COMM_WORLD,"Number of iterations = %d\n",its);
31: KSPGetResidualNorm(*ksp,&norm);
32: if (norm < 1.e-12) {
33: PetscPrintf(PETSC_COMM_WORLD,"Residual norm < 1.e-12\n");
34: } else {
35: PetscPrintf(PETSC_COMM_WORLD,"Residual norm %e\n",(double)norm);
36: }
38: KSPDestroy(ksp);
39: MatDestroy(A);
40: VecDestroy(x);
41: VecDestroy(b);
42: ISDestroy(rowperm);
43: return 0;
44: }
46: PetscErrorCode CreateSystem(const char filename[PETSC_MAX_PATH_LEN], RHSType rhstype, MatOrderingType ordering, PetscBool permute, IS *rowperm_out, Mat *A_out, Vec *b_out, Vec *x_out)
47: {
49: Vec x,b,b2;
50: Mat A; /* linear system matrix */
51: PetscViewer viewer; /* viewer */
52: PetscBool same;
53: PetscInt j,len,start,idx,n1,n2;
54: const PetscScalar *val;
55: IS rowperm=NULL,colperm=NULL;
57: /* open binary file. Note that we use FILE_MODE_READ to indicate reading from this file */
58: PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);
60: /* load the matrix and vector; then destroy the viewer */
61: MatCreate(PETSC_COMM_WORLD,&A);
62: MatSetFromOptions(A);
63: MatLoad(A,viewer);
64: switch (rhstype) {
65: case RHS_FILE:
66: /* Vectors in the file might a different size than the matrix so we need a
67: * Vec whose size hasn't been set yet. It'll get fixed below. Otherwise we
68: * can create the correct size Vec. */
69: VecCreate(PETSC_COMM_WORLD,&b);
70: VecLoad(b,viewer);
71: break;
72: case RHS_ONE:
73: MatCreateVecs(A,&b,NULL);
74: VecSet(b,1.0);
75: break;
76: case RHS_RANDOM:
77: MatCreateVecs(A,&b,NULL);
78: VecSetRandom(b,NULL);
79: break;
80: }
81: PetscViewerDestroy(&viewer);
83: /* if the loaded matrix is larger than the vector (due to being padded
84: to match the block size of the system), then create a new padded vector
85: */
86: MatGetLocalSize(A,NULL,&n1);
87: VecGetLocalSize(b,&n2);
88: same = (n1 == n2)? PETSC_TRUE : PETSC_FALSE;
89: MPIU_Allreduce(MPI_IN_PLACE,&same,1,MPIU_BOOL,MPI_LAND,PETSC_COMM_WORLD);
91: if (!same) { /* create a new vector b by padding the old one */
92: VecCreate(PETSC_COMM_WORLD,&b2);
93: VecSetSizes(b2,n1,PETSC_DECIDE);
94: VecSetFromOptions(b2);
95: VecGetOwnershipRange(b,&start,NULL);
96: VecGetLocalSize(b,&len);
97: VecGetArrayRead(b,&val);
98: for (j=0; j<len; j++) {
99: idx = start+j;
100: VecSetValues(b2,1,&idx,val+j,INSERT_VALUES);
101: }
102: VecRestoreArrayRead(b,&val);
103: VecDestroy(&b);
104: VecAssemblyBegin(b2);
105: VecAssemblyEnd(b2);
106: b = b2;
107: }
108: VecDuplicate(b,&x);
110: if (permute) {
111: Mat Aperm;
112: MatGetOrdering(A,ordering,&rowperm,&colperm);
113: MatPermute(A,rowperm,colperm,&Aperm);
114: VecPermute(b,colperm,PETSC_FALSE);
115: MatDestroy(&A);
116: A = Aperm; /* Replace original operator with permuted version */
117: ISDestroy(&colperm);
118: }
120: *b_out = b;
121: *x_out = x;
122: *A_out = A;
123: *rowperm_out = rowperm;
125: return 0;
126: }
128: /* ATTENTION: this is the example used in the Profiling chaper of the PETSc manual,
129: where we referenced its profiling stages, preloading and output etc.
130: When you modify it, please make sure it is still consistent with the manual.
131: */
132: int main(int argc,char **args)
133: {
134: PetscErrorCode ierr;
135: Vec x,b;
136: Mat A; /* linear system matrix */
137: KSP ksp; /* Krylov subspace method context */
138: char file[2][PETSC_MAX_PATH_LEN],ordering[256]=MATORDERINGRCM;
139: RHSType rhstype = RHS_FILE;
140: PetscBool flg,preload=PETSC_FALSE,trans=PETSC_FALSE,permute=PETSC_FALSE;
141: IS rowperm=NULL;
143: PetscInitialize(&argc,&args,(char*)0,help);
145: PetscOptionsBegin(PETSC_COMM_WORLD,NULL,"Preloading example options","");
146: {
147: /*
148: Determine files from which we read the two linear systems
149: (matrix and right-hand-side vector).
150: */
151: PetscOptionsBool("-trans","Solve transpose system instead","",trans,&trans,&flg);
152: PetscOptionsString("-f","First file to load (small system)","",file[0],file[0],sizeof(file[0]),&flg);
153: PetscOptionsFList("-permute","Permute matrix and vector to solve in new ordering","",MatOrderingList,ordering,ordering,sizeof(ordering),&permute);
155: if (flg) {
156: PetscStrcpy(file[1],file[0]);
157: preload = PETSC_FALSE;
158: } else {
159: PetscOptionsString("-f0","First file to load (small system)","",file[0],file[0],sizeof(file[0]),&flg);
161: PetscOptionsString("-f1","Second file to load (larger system)","",file[1],file[1],sizeof(file[1]),&flg);
162: if (!flg) preload = PETSC_FALSE; /* don't bother with second system */
163: }
165: PetscOptionsEnum("-rhs","Right hand side","",RHSTypes,(PetscEnum)rhstype,(PetscEnum*)&rhstype,NULL);
166: }
167: PetscOptionsEnd();
169: /*
170: To use preloading, one usually has code like the following:
172: PetscPreLoadBegin(preload,"first stage);
173: lines of code
174: PetscPreLoadStage("second stage");
175: lines of code
176: PetscPreLoadEnd();
178: The two macro PetscPreLoadBegin() and PetscPreLoadEnd() implicitly form a
179: loop with maximal two iterations, depending whether preloading is turned on or
180: not. If it is, either through the preload arg of PetscPreLoadBegin or through
181: -preload command line, the trip count is 2, otherwise it is 1. One can use the
182: predefined variable PetscPreLoadIt within the loop body to get the current
183: iteration number, which is 0 or 1. If preload is turned on, the runtime doesn't
184: do profiling for the first iteration, but it will do profiling for the second
185: iteration instead.
187: One can solve a small system in the first iteration and a large system in
188: the second iteration. This process preloads the instructions with the small
189: system so that more accurate performance monitoring (via -log_view) can be done
190: with the large one (that actually is the system of interest).
192: But in this example, we turned off preloading and duplicated the code for
193: the large system. In general, it is a bad practice and one should not duplicate
194: code. We do that because we want to show profiling stages for both the small
195: system and the large system.
196: */
198: /*=========================
199: solve a small system
200: =========================*/
202: PetscPreLoadBegin(preload,"Load System 0");
203: CreateSystem(file[0],rhstype,ordering,permute,&rowperm,&A,&b,&x);
205: PetscPreLoadStage("KSPSetUp 0");
206: KSPCreate(PETSC_COMM_WORLD,&ksp);
207: KSPSetOperators(ksp,A,A);
208: KSPSetFromOptions(ksp);
210: /*
211: Here we explicitly call KSPSetUp() and KSPSetUpOnBlocks() to
212: enable more precise profiling of setting up the preconditioner.
213: These calls are optional, since both will be called within
214: KSPSolve() if they haven't been called already.
215: */
216: KSPSetUp(ksp);
217: KSPSetUpOnBlocks(ksp);
219: PetscPreLoadStage("KSPSolve 0");
220: if (trans) KSPSolveTranspose(ksp,b,x);
221: else KSPSolve(ksp,b,x);
223: if (permute) VecPermute(x,rowperm,PETSC_TRUE);
225: CheckResult(&ksp,&A,&b,&x,&rowperm);
227: /*=========================
228: solve a large system
229: =========================*/
231: PetscPreLoadStage("Load System 1");
233: CreateSystem(file[1],rhstype,ordering,permute,&rowperm,&A,&b,&x);
235: PetscPreLoadStage("KSPSetUp 1");
236: KSPCreate(PETSC_COMM_WORLD,&ksp);
237: KSPSetOperators(ksp,A,A);
238: KSPSetFromOptions(ksp);
240: /*
241: Here we explicitly call KSPSetUp() and KSPSetUpOnBlocks() to
242: enable more precise profiling of setting up the preconditioner.
243: These calls are optional, since both will be called within
244: KSPSolve() if they haven't been called already.
245: */
246: KSPSetUp(ksp);
247: KSPSetUpOnBlocks(ksp);
249: PetscPreLoadStage("KSPSolve 1");
250: if (trans) KSPSolveTranspose(ksp,b,x);
251: else KSPSolve(ksp,b,x);
253: if (permute) VecPermute(x,rowperm,PETSC_TRUE);
255: CheckResult(&ksp,&A,&b,&x,&rowperm);
257: PetscPreLoadEnd();
258: /*
259: Always call PetscFinalize() before exiting a program. This routine
260: - finalizes the PETSc libraries as well as MPI
261: - provides summary and diagnostic information if certain runtime
262: options are chosen (e.g., -log_view).
263: */
264: PetscFinalize();
265: return 0;
266: }
268: /*TEST
270: test:
271: TODO: Matrix row/column sizes are not compatible with block size
272: suffix: 1
273: nsize: 4
274: output_file: output/ex10_1.out
275: requires: datafilespath double !complex !defined(PETSC_USE_64BIT_INDICES)
276: args: -f0 ${DATAFILESPATH}/matrices/medium -f1 ${DATAFILESPATH}/matrices/arco6 -ksp_gmres_classicalgramschmidt -mat_type baij -matload_block_size 3 -pc_type bjacobi
278: test:
279: TODO: Matrix row/column sizes are not compatible with block size
280: suffix: 2
281: nsize: 4
282: output_file: output/ex10_2.out
283: requires: datafilespath double !complex !defined(PETSC_USE_64BIT_INDICES)
284: args: -f0 ${DATAFILESPATH}/matrices/medium -f1 ${DATAFILESPATH}/matrices/arco6 -ksp_gmres_classicalgramschmidt -mat_type baij -matload_block_size 3 -pc_type bjacobi -trans
286: test:
287: suffix: 3
288: requires: double complex !defined(PETSC_USE_64BIT_INDICES)
289: args: -f ${wPETSC_DIR}/share/petsc/datafiles/matrices/nh-complex-int32-float64 -ksp_type bicg
291: test:
292: suffix: 4
293: args: -f ${DATAFILESPATH}/matrices/medium -ksp_type bicg -permute rcm
294: requires: datafilespath double !complex !defined(PETSC_USE_64BIT_INDICES)
296: TEST*/