Actual source code: ex10.c

  2: static char help[] = "Reads a PETSc matrix and vector from a file and solves a linear system.\n\
  3: This version first preloads and solves a small system, then loads \n\
  4: another (larger) system and solves it as well.  This example illustrates\n\
  5: preloading of instructions with the smaller system so that more accurate\n\
  6: performance monitoring can be done with the larger one (that actually\n\
  7: is the system of interest).  See the 'Performance Hints' chapter of the\n\
  8: users manual for a discussion of preloading.  Input parameters include\n\
  9:   -f0 <input_file> : first file to load (small system)\n\
 10:   -f1 <input_file> : second file to load (larger system)\n\n\
 11:   -trans  : solve transpose system instead\n\n";
 12: /*
 13:   This code can be used to test PETSc interface to other packages.\n\
 14:   Examples of command line options:       \n\
 15:    ./ex10 -f0 <datafile> -ksp_type preonly  \n\
 16:         -help -ksp_view                  \n\
 17:         -num_numfac <num_numfac> -num_rhs <num_rhs> \n\
 18:         -ksp_type preonly -pc_type lu -pc_factor_mat_solver_package spooles or superlu or superlu_dist or mumps \n\
 19:         -ksp_type preonly -pc_type cholesky -pc_factor_mat_solver_package spooles or dscpack or mumps \n\   
 20:    mpiexec -n <np> ./ex10 -f0 <datafile> -ksp_type cg -pc_type asm -pc_asm_type basic -sub_pc_type icc -mat_type sbaij
 21:  \n\n";
 22: */
 23: /*T
 24:    Concepts: KSP^solving a linear system
 25:    Processors: n
 26: T*/

 28: /* 
 29:   Include "petscksp.h" so that we can use KSP solvers.  Note that this file
 30:   automatically includes:
 31:      petscsys.h       - base PETSc routines   petscvec.h - vectors
 32:      petscmat.h - matrices
 33:      petscis.h     - index sets            petscksp.h - Krylov subspace methods
 34:      petscviewer.h - viewers               petscpc.h  - preconditioners
 35: */
 36:  #include petscksp.h

 40: int main(int argc,char **args)
 41: {
 42:   KSP            ksp;             /* linear solver context */
 43:   Mat            A,B = 0;            /* matrix */
 44:   Vec            x,b,u;          /* approx solution, RHS, exact solution */
 45:   PetscViewer    fd;               /* viewer */
 46:   char           file[4][PETSC_MAX_PATH_LEN];     /* input file name */
 47:   PetscTruth     table=PETSC_FALSE,flg,flgB=PETSC_FALSE,trans=PETSC_FALSE,initialguess = PETSC_FALSE;
 48:   PetscTruth     outputSoln=PETSC_FALSE;
 50:   PetscInt       its,num_numfac,m,n,M;
 51:   PetscReal      norm;
 52:   PetscLogDouble tsetup,tsetup1,tsetup2,tsolve,tsolve1,tsolve2;
 53:   PetscTruth     preload=PETSC_TRUE,isSymmetric,cknorm=PETSC_FALSE,initialguessfile = PETSC_FALSE;
 54:   PetscMPIInt    rank;
 55:   char           initialguessfilename[PETSC_MAX_PATH_LEN];

 57:   PetscInitialize(&argc,&args,(char *)0,help);
 58:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
 59:   PetscOptionsGetTruth(PETSC_NULL,"-table",&table,PETSC_NULL);
 60:   PetscOptionsGetTruth(PETSC_NULL,"-trans",&trans,PETSC_NULL);
 61:   PetscOptionsGetTruth(PETSC_NULL,"-initialguess",&initialguess,PETSC_NULL);
 62:   PetscOptionsGetTruth(PETSC_NULL,"-output_solution",&outputSoln,PETSC_NULL);
 63:   PetscOptionsGetString(PETSC_NULL,"-initialguessfilename",initialguessfilename,PETSC_MAX_PATH_LEN-1,&initialguessfile);

 65:   /* 
 66:      Determine files from which we read the two linear systems
 67:      (matrix and right-hand-side vector).
 68:   */
 69:   PetscOptionsGetString(PETSC_NULL,"-f",file[0],PETSC_MAX_PATH_LEN-1,&flg);
 70:   if (flg) {
 71:     PetscStrcpy(file[1],file[0]);
 72:     preload = PETSC_FALSE;
 73:   } else {
 74:     PetscOptionsGetString(PETSC_NULL,"-f0",file[0],PETSC_MAX_PATH_LEN-1,&flg);
 75:     if (!flg) SETERRQ(1,"Must indicate binary file with the -f0 or -f option");
 76:     PetscOptionsGetString(PETSC_NULL,"-f1",file[1],PETSC_MAX_PATH_LEN-1,&flg);
 77:     if (!flg) {preload = PETSC_FALSE;} /* don't bother with second system */
 78:   }

 80:   /* -----------------------------------------------------------
 81:                   Beginning of linear solver loop
 82:      ----------------------------------------------------------- */
 83:   /* 
 84:      Loop through the linear solve 2 times.  
 85:       - The intention here is to preload and solve a small system;
 86:         then load another (larger) system and solve it as well.
 87:         This process preloads the instructions with the smaller
 88:         system so that more accurate performance monitoring (via
 89:         -log_summary) can be done with the larger one (that actually
 90:         is the system of interest). 
 91:   */
 92:   PreLoadBegin(preload,"Load system");

 94:     /* - - - - - - - - - - - New Stage - - - - - - - - - - - - -
 95:                            Load system
 96:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

 98:     /* 
 99:        Open binary file.  Note that we use FILE_MODE_READ to indicate
100:        reading from this file.
101:     */
102:     PetscViewerBinaryOpen(PETSC_COMM_WORLD,file[PreLoadIt],FILE_MODE_READ,&fd);
103: 
104:     /*
105:        Load the matrix and vector; then destroy the viewer.
106:     */
107:     MatLoad(fd,MATAIJ,&A);
108: 
109:     if (!preload){
110:       flg = PETSC_FALSE;
111:       PetscOptionsGetString(PETSC_NULL,"-rhs",file[2],PETSC_MAX_PATH_LEN-1,&flg);
112:       if (flg){ /* rhs is stored in a separate file */
113:         if (file[2][0] == '0') {
114:           PetscInt    m;
115:           PetscScalar one = 1.0;
116:           PetscInfo(0,"Using vector of ones for RHS\n");
117:           MatGetLocalSize(A,&m,PETSC_NULL);
118:           VecCreate(PETSC_COMM_WORLD,&b);
119:           VecSetSizes(b,m,PETSC_DECIDE);
120:           VecSetFromOptions(b);
121:           VecSet(b,one);
122:         } else {
123:           PetscViewerDestroy(fd);
124:           PetscViewerBinaryOpen(PETSC_COMM_WORLD,file[2],FILE_MODE_READ,&fd);
125:           VecLoad(fd,PETSC_NULL,&b);
126:         }
127:       } else {
128:         VecLoad(fd,PETSC_NULL,&b);
129:       }
130:     }
131:     PetscViewerDestroy(fd);

133:     /* Make A singular for testing zero-pivot of ilu factorization        */
134:     /* Example: ./ex10 -f0 <datafile> -test_zeropivot -set_row_zero -pc_factor_shift_nonzero */
135:     flg  = PETSC_FALSE;
136:     PetscOptionsGetTruth(PETSC_NULL, "-test_zeropivot", &flg,PETSC_NULL);
137:     if (flg) {
138:       PetscInt          row,ncols;
139:       const PetscInt    *cols;
140:       const PetscScalar *vals;
141:       PetscTruth        flg1=PETSC_FALSE;
142:       PetscScalar       *zeros;
143:       row = 0;
144:       MatGetRow(A,row,&ncols,&cols,&vals);
145:       PetscMalloc(sizeof(PetscScalar)*(ncols+1),&zeros);
146:       PetscMemzero(zeros,(ncols+1)*sizeof(PetscScalar));
147:       PetscOptionsGetTruth(PETSC_NULL, "-set_row_zero", &flg1,PETSC_NULL);
148:       if (flg1){ /* set entire row as zero */
149:         MatSetValues(A,1,&row,ncols,cols,zeros,INSERT_VALUES);
150:       } else { /* only set (row,row) entry as zero */
151:         MatSetValues(A,1,&row,1,&row,zeros,INSERT_VALUES);
152:       }
153:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
154:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
155:     }

157:     /* Check whether A is symmetric */
158:     flg  = PETSC_FALSE;
159:     PetscOptionsGetTruth(PETSC_NULL, "-check_symmetry", &flg,PETSC_NULL);
160:     if (flg) {
161:       Mat Atrans;
162:       MatTranspose(A, MAT_INITIAL_MATRIX,&Atrans);
163:       MatEqual(A, Atrans, &isSymmetric);
164:       if (isSymmetric) {
165:         MatSetOption(A,MAT_SYMMETRIC,PETSC_TRUE);
166:       } else {
167:         PetscPrintf(PETSC_COMM_WORLD,"Warning: A is non-symmetric \n");
168:       }
169:       MatDestroy(Atrans);
170:     }

172:     /* 
173:        If the loaded matrix is larger than the vector (due to being padded 
174:        to match the block size of the system), then create a new padded vector.
175:     */
176: 
177:     MatGetLocalSize(A,&m,&n);
178:     if (m != n) {
179:       SETERRQ2(PETSC_ERR_ARG_SIZ, "This example is not intended for rectangular matrices (%d, %d)", m, n);
180:     }
181:     MatGetSize(A,&M,PETSC_NULL);
182:     VecGetSize(b,&m);
183:     if (M != m) { /* Create a new vector b by padding the old one */
184:       PetscInt    j,mvec,start,end,indx;
185:       Vec         tmp;
186:       PetscScalar *bold;

188:       VecCreate(PETSC_COMM_WORLD,&tmp);
189:       VecSetSizes(tmp,n,PETSC_DECIDE);
190:       VecSetFromOptions(tmp);
191:       VecGetOwnershipRange(b,&start,&end);
192:       VecGetLocalSize(b,&mvec);
193:       VecGetArray(b,&bold);
194:       for (j=0; j<mvec; j++) {
195:         indx = start+j;
196:         VecSetValues(tmp,1,&indx,bold+j,INSERT_VALUES);
197:       }
198:       VecRestoreArray(b,&bold);
199:       VecDestroy(b);
200:       VecAssemblyBegin(tmp);
201:       VecAssemblyEnd(tmp);
202:       b = tmp;
203:     }
204:     VecDuplicate(b,&x);
205:     VecDuplicate(b,&u);
206:     if (initialguessfile) {
207:       PetscViewer viewer2;
208:       PetscViewerBinaryOpen(PETSC_COMM_WORLD,initialguessfilename,FILE_MODE_READ,&viewer2);
209:       VecLoadIntoVector(viewer2,x);
210:       PetscViewerDestroy(viewer2);
211:       initialguess = PETSC_TRUE;
212:     } else {
213:       VecSet(x,0.0);
214:     }


217:     /* Check scaling in A */
218:     flg  = PETSC_FALSE;
219:     PetscOptionsGetTruth(PETSC_NULL, "-check_scaling", &flg,PETSC_NULL);
220:     if (flg) {
221:       Vec         max, min;
222:       PetscInt    idx;
223:       PetscReal   val;

225:       VecDuplicate(x, &max);
226:       VecDuplicate(x, &min);
227:       MatGetRowMaxAbs(A, max, PETSC_NULL);
228:       MatGetRowMinAbs(A, min, PETSC_NULL);
229:       {
230:         PetscViewer viewer;

232:         PetscViewerASCIIOpen(PETSC_COMM_WORLD, "max.data", &viewer);
233:         VecView(max, viewer);
234:         PetscViewerDestroy(viewer);
235:         PetscViewerASCIIOpen(PETSC_COMM_WORLD, "min.data", &viewer);
236:         VecView(min, viewer);
237:         PetscViewerDestroy(viewer);
238:       }
239:       VecView(max, PETSC_VIEWER_DRAW_WORLD);
240:       VecMax(max, &idx, &val);
241:       PetscPrintf(PETSC_COMM_WORLD, "Largest max row element %G at row %d\n", val, idx);
242:       VecView(min, PETSC_VIEWER_DRAW_WORLD);
243:       VecMin(min, &idx, &val);
244:       PetscPrintf(PETSC_COMM_WORLD, "Smallest min row element %G at row %d\n", val, idx);
245:       VecMin(max, &idx, &val);
246:       PetscPrintf(PETSC_COMM_WORLD, "Smallest max row element %G at row %d\n", val, idx);
247:       VecPointwiseDivide(max, max, min);
248:       VecMax(max, &idx, &val);
249:       PetscPrintf(PETSC_COMM_WORLD, "Largest row ratio %G at row %d\n", val, idx);
250:       VecView(max, PETSC_VIEWER_DRAW_WORLD);
251:       VecDestroy(max);
252:       VecDestroy(min);
253:     }

255:     /* - - - - - - - - - - - New Stage - - - - - - - - - - - - -
256:                       Setup solve for system
257:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
258:     /*
259:        Conclude profiling last stage; begin profiling next stage.
260:     */
261:     PreLoadStage("KSPSetUpSolve");

263:     /*
264:        We also explicitly time this stage via PetscGetTime()
265:     */
266:     PetscGetTime(&tsetup1);

268:     /*
269:        Create linear solver; set operators; set runtime options.
270:     */
271:     KSPCreate(PETSC_COMM_WORLD,&ksp);
272:     KSPSetInitialGuessNonzero(ksp,initialguess);
273:     num_numfac = 1;
274:     PetscOptionsGetInt(PETSC_NULL,"-num_numfac",&num_numfac,PETSC_NULL);
275:     while ( num_numfac-- ){
276:       PetscTruth lsqr;
277:       char       str[32];
278:       PetscOptionsGetString(PETSC_NULL,"-ksp_type",str,32,&lsqr);
279:       if (lsqr) {
280:         PetscStrcmp("lsqr",str,&lsqr);
281:       }
282:       if (lsqr) {
283:         Mat B;
284:         MatMatMultTranspose(A,A,MAT_INITIAL_MATRIX,4,&B);
285:         KSPSetOperators(ksp,A,B,SAME_NONZERO_PATTERN);
286:         MatDestroy(B);
287:       } else {
288:         KSPSetOperators(ksp,A,A,SAME_NONZERO_PATTERN);
289:       }
290:       KSPSetFromOptions(ksp);

292:       /* 
293:        Here we explicitly call KSPSetUp() and KSPSetUpOnBlocks() to
294:        enable more precise profiling of setting up the preconditioner.
295:        These calls are optional, since both will be called within
296:        KSPSolve() if they haven't been called already.
297:       */
298:       KSPSetUp(ksp);
299:       KSPSetUpOnBlocks(ksp);
300:       PetscGetTime(&tsetup2);
301:       tsetup = tsetup2 - tsetup1;

303:       /* - - - - - - - - - - - New Stage - - - - - - - - - - - - -
304:                            Solve system
305:         - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

307:       /*
308:        Solve linear system; we also explicitly time this stage.
309:       */
310:       PetscGetTime(&tsolve1);
311:       if (trans) {
312:         KSPSolveTranspose(ksp,b,x);
313:         KSPGetIterationNumber(ksp,&its);
314:       } else {
315:         PetscInt  num_rhs=1;
316:         PetscOptionsGetInt(PETSC_NULL,"-num_rhs",&num_rhs,PETSC_NULL);
317:         cknorm = PETSC_FALSE;
318:         PetscOptionsGetTruth(PETSC_NULL,"-cknorm",&cknorm,PETSC_NULL);
319:         while ( num_rhs-- ) {
320:           if (num_rhs == 1) VecSet(x,0.0);
321:           KSPSolve(ksp,b,x);
322:         }
323:         KSPGetIterationNumber(ksp,&its);
324:         if (cknorm){   /* Check error for each rhs */
325:           if (trans) {
326:             MatMultTranspose(A,x,u);
327:           } else {
328:             MatMult(A,x,u);
329:           }
330:           VecAXPY(u,-1.0,b);
331:           VecNorm(u,NORM_2,&norm);
332:           PetscPrintf(PETSC_COMM_WORLD,"  Number of iterations = %3D\n",its);
333:           PetscPrintf(PETSC_COMM_WORLD,"  Residual norm %A\n",norm);
334:         }
335:       } /* while ( num_rhs-- ) */
336:       PetscGetTime(&tsolve2);
337:       tsolve = tsolve2 - tsolve1;

339:       /* - - - - - - - - - - - New Stage - - - - - - - - - - - - -
340:             Check error, print output, free data structures.
341:        - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

343:       /* 
344:          Check error
345:       */
346:       if (trans) {
347:         MatMultTranspose(A,x,u);
348:       } else {
349:         MatMult(A,x,u);
350:       }
351:       VecAXPY(u,-1.0,b);
352:       VecNorm(u,NORM_2,&norm);

354:       /*
355:        Write output (optinally using table for solver details).
356:         - PetscPrintf() handles output for multiprocessor jobs 
357:           by printing from only one processor in the communicator.
358:         - KSPView() prints information about the linear solver.
359:       */
360:       if (table) {
361:         char        *matrixname,kspinfo[120];
362:         PetscViewer viewer;

364:         /*
365:          Open a string viewer; then write info to it.
366:         */
367:         PetscViewerStringOpen(PETSC_COMM_WORLD,kspinfo,120,&viewer);
368:         KSPView(ksp,viewer);
369:         PetscStrrchr(file[PreLoadIt],'/',&matrixname);
370:         PetscPrintf(PETSC_COMM_WORLD,"%-8.8s %3D %2.0e %2.1e %2.1e %2.1e %s \n",
371:                 matrixname,its,norm,tsetup+tsolve,tsetup,tsolve,kspinfo);

373:         /*
374:           Destroy the viewer
375:         */
376:         PetscViewerDestroy(viewer);
377:       } else {
378:         PetscPrintf(PETSC_COMM_WORLD,"Number of iterations = %3D\n",its);
379:         PetscPrintf(PETSC_COMM_WORLD,"Residual norm %A\n",norm);
380:       }
381:       PetscOptionsGetString(PETSC_NULL,"-solution",file[3],PETSC_MAX_PATH_LEN-1,&flg);
382:       if (flg) {
383:         PetscViewer viewer;
384:         Vec         xstar;
385:         PetscReal   norm;

387:         PetscViewerBinaryOpen(PETSC_COMM_WORLD,file[3],FILE_MODE_READ,&viewer);
388:         VecLoad(viewer, VECMPI, &xstar);
389:         VecAXPY(xstar, -1.0, x);
390:         VecNorm(xstar, NORM_2, &norm);
391:         PetscPrintf(PETSC_COMM_WORLD, "Error norm %A\n", norm);
392:         VecDestroy(xstar);
393:         PetscViewerDestroy(viewer);
394:       }
395:       if (outputSoln) {
396:         PetscViewer viewer;

398:         PetscViewerBinaryOpen(PETSC_COMM_WORLD,"solution.petsc",FILE_MODE_WRITE,&viewer);
399:         VecView(x, viewer);
400:         PetscViewerDestroy(viewer);
401:       }

403:       flg  = PETSC_FALSE;
404:       PetscOptionsGetTruth(PETSC_NULL, "-ksp_reason", &flg,PETSC_NULL);
405:       if (flg){
406:         KSPConvergedReason reason;
407:         KSPGetConvergedReason(ksp,&reason);
408:         PetscPrintf(PETSC_COMM_WORLD,"KSPConvergedReason: %D\n", reason);
409:       }
410: 
411:     } /* while ( num_numfac-- ) */

413:     /* 
414:        Free work space.  All PETSc objects should be destroyed when they
415:        are no longer needed.
416:     */
417:     MatDestroy(A); VecDestroy(b);
418:     VecDestroy(u); VecDestroy(x);
419:     KSPDestroy(ksp);
420:     if (flgB) { MatDestroy(B); }
421:   PreLoadEnd();
422:   /* -----------------------------------------------------------
423:                       End of linear solver loop
424:      ----------------------------------------------------------- */

426:   PetscFinalize();
427:   return 0;
428: }