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1 c
2 c Example 12
3 c
4 c Interface: Semi-Structured interface (SStruct)
5 c
6 c Compile with: make ex12f (may need to edit HYPRE_DIR in Makefile)
7 c
8 c Sample runs: mpirun -np 2 ex12f
9 c
10 c Description: The grid layout is the same as ex1, but with nodal
11 c unknowns. The solver is PCG preconditioned with either PFMG or
12 c BoomerAMG, set with 'precond_id' below.
13 c
14 c We recommend viewing the Struct examples before viewing this and
15 c the other SStruct examples. This is one of the simplest SStruct
16 c examples, used primarily to demonstrate how to set up
17 c non-cell-centered problems, and to demonstrate how easy it is to
18 c switch between structured solvers (PFMG) and solvers designed for
19 c more general settings (AMG).
20 c
21
22 program ex12f
23
24 implicit none
25
26 include 'mpif.h'
27 include 'HYPREf.h'
28
29 integer ierr
30 integer i, j, myid, num_procs
31
32 integer*8 grid
33 integer*8 graph
34 integer*8 stencil
35 integer*8 A
36 integer*8 b
37 integer*8 x
38
39 integer nparts
40 integer nvars
41 integer part
42 integer var
43
44 integer precond_id, object_type
45
46 integer ilower(2), iupper(2)
47 integer vartypes(1)
48 integer offsets(2,5)
49 integer ent
50 integer nentries, nvalues, stencil_indices(5)
51
52 double precision values(100), tol
53
54 c This comes from 'sstruct_mv/HYPRE_sstruct_mv.h'
55 integer HYPRE_SSTRUCT_VARIABLE_NODE
56 parameter( HYPRE_SSTRUCT_VARIABLE_NODE = 1 )
57
58 integer*8 sA
59 integer*8 sb
60 integer*8 sx
61 integer*8 parA
62 integer*8 parb
63 integer*8 parx
64 integer*8 solver
65 integer*8 precond
66
67 character*32 matfile
68
69 c We only have one part and one variable
70 nparts = 1
71 nvars = 1
72 part = 0
73 var = 0
74
75 c Initialize MPI
76 call MPI_Init(ierr)
77 call MPI_Comm_rank(MPI_COMM_WORLD, myid, ierr)
78 call MPI_Comm_size(MPI_COMM_WORLD, num_procs, ierr)
79
80 if (num_procs .ne. 2) then
81 if (myid .eq. 0) then
82 print *, "Must run with 2 processors!"
83 stop
84 endif
85 endif
86
87 c Set preconditioner id (PFMG = 1, BoomerAMG = 2)
88 precond_id = 1
89
90 if (precond_id .eq. 1) then
91 object_type = HYPRE_STRUCT
92 else if (precond_id .eq. 2) then
93 object_type = HYPRE_PARCSR
94 else
95 if (myid .eq. 0) then
96 print *, "Invalid solver!"
97 stop
98 endif
99 endif
100
101 c-----------------------------------------------------------------------
102 c 1. Set up the grid. Here we use only one part. Each processor
103 c describes the piece of the grid that it owns.
104 c-----------------------------------------------------------------------
105
106 c Create an empty 2D grid object
107 call HYPRE_SStructGridCreate(MPI_COMM_WORLD, 2, nparts, grid,
108 + ierr)
109
110 c Add boxes to the grid
111 if (myid .eq. 0) then
112 ilower(1) = -3
113 ilower(2) = 1
114 iupper(1) = -1
115 iupper(2) = 2
116 call HYPRE_SStructGridSetExtents(grid, part, ilower, iupper,
117 + ierr)
118 else if (myid .eq. 1) then
119 ilower(1) = 0
120 ilower(2) = 1
121 iupper(1) = 2
122 iupper(2) = 4
123 call HYPRE_SStructGridSetExtents(grid, part, ilower, iupper,
124 + ierr)
125 endif
126
127 c Set the variable type and number of variables on each part
128 vartypes(1) = HYPRE_SSTRUCT_VARIABLE_NODE
129 call HYPRE_SStructGridSetVariables(grid, part, nvars, vartypes,
130 + ierr)
131
132 c This is a collective call finalizing the grid assembly
133 call HYPRE_SStructGridAssemble(grid, ierr)
134
135 c-----------------------------------------------------------------------
136 c 2. Define the discretization stencil
137 c-----------------------------------------------------------------------
138
139 c Create an empty 2D, 5-pt stencil object
140 call HYPRE_SStructStencilCreate(2, 5, stencil, ierr)
141
142 c Define the geometry of the stencil. Each represents a relative
143 c offset (in the index space).
144 offsets(1,1) = 0
145 offsets(2,1) = 0
146 offsets(1,2) = -1
147 offsets(2,2) = 0
148 offsets(1,3) = 1
149 offsets(2,3) = 0
150 offsets(1,4) = 0
151 offsets(2,4) = -1
152 offsets(1,5) = 0
153 offsets(2,5) = 1
154
155 c Assign numerical values to the offsets so that we can easily refer
156 c to them - the last argument indicates the variable for which we
157 c are assigning this stencil
158 do ent = 1, 5
159 call HYPRE_SStructStencilSetEntry(stencil,
160 + ent-1, offsets(1,ent), var, ierr)
161 enddo
162
163 c-----------------------------------------------------------------------
164 c 3. Set up the Graph - this determines the non-zero structure of
165 c the matrix and allows non-stencil relationships between the parts
166 c-----------------------------------------------------------------------
167
168 c Create the graph object
169 call HYPRE_SStructGraphCreate(MPI_COMM_WORLD, grid, graph, ierr)
170
171 c Now we need to tell the graph which stencil to use for each
172 c variable on each part (we only have one variable and one part)
173 call HYPRE_SStructGraphSetStencil(graph, part, var, stencil, ierr)
174
175 c Here we could establish connections between parts if we had more
176 c than one part using the graph. For example, we could use
177 c HYPRE_GraphAddEntries() routine or HYPRE_GridSetNeighborPart()
178
179 c Assemble the graph
180 call HYPRE_SStructGraphAssemble(graph, ierr)
181
182 c-----------------------------------------------------------------------
183 c 4. Set up a SStruct Matrix
184 c-----------------------------------------------------------------------
185
186 c Create an empty matrix object
187 call HYPRE_SStructMatrixCreate(MPI_COMM_WORLD, graph, A, ierr)
188
189 c Set the object type (by default HYPRE_SSTRUCT). This determines
190 c the data structure used to store the matrix. For PFMG we use
191 c HYPRE_STRUCT, and for BoomerAMG we use HYPRE_PARCSR (set above).
192 call HYPRE_SStructMatrixSetObjectTyp(A, object_type, ierr)
193
194 c Get ready to set values
195 call HYPRE_SStructMatrixInitialize(A, ierr)
196
197 c Set the matrix coefficients. Each processor assigns coefficients
198 c for the boxes in the grid that it owns. Note that the
199 c coefficients associated with each stencil entry may vary from grid
200 c point to grid point if desired. Here, we first set the same
201 c stencil entries for each grid point. Then we make modifications
202 c to grid points near the boundary. Note that the ilower values are
203 c different from those used in ex1 because of the way nodal
204 c variables are referenced. Also note that some of the stencil
205 c values are set on both processor 0 and processor 1. See the User
206 c and Reference manuals for more details.
207
208 c Stencil entry labels correspond to the offsets defined above
209 do i = 1, 5
210 stencil_indices(i) = i-1
211 enddo
212 nentries = 5
213
214 if (myid .eq. 0) then
215 ilower(1) = -4
216 ilower(2) = 0
217 iupper(1) = -1
218 iupper(2) = 2
219 c 12 grid points, each with 5 stencil entries
220 nvalues = 60
221 else if (myid .eq. 1) then
222 ilower(1) = -1
223 ilower(2) = 0
224 iupper(1) = 2
225 iupper(2) = 4
226 c 12 grid points, each with 5 stencil entries
227 nvalues = 100
228 endif
229
230 do i = 1, nvalues, nentries
231 values(i) = 4.0
232 do j = 1, nentries-1
233 values(i+j) = -1.0
234 enddo
235 enddo
236
237 call HYPRE_SStructMatrixSetBoxValues(A, part, ilower, iupper,
238 + var, nentries, stencil_indices, values, ierr)
239
240 c Set the coefficients reaching outside of the boundary to 0. Note
241 c that both ilower *and* iupper may be different from those in ex1.
242
243 do i = 1, 5
244 values(i) = 0.0
245 enddo
246
247 if (myid .eq. 0) then
248
249 c values below our box
250 ilower(1) = -4
251 ilower(2) = 0
252 iupper(1) = -1
253 iupper(2) = 0
254 stencil_indices(1) = 3
255 call HYPRE_SStructMatrixSetBoxValues(A, part, ilower, iupper,
256 + var, 1, stencil_indices, values, ierr)
257 c values to the left of our box
258 ilower(1) = -4
259 ilower(2) = 0
260 iupper(1) = -4
261 iupper(2) = 2
262 stencil_indices(1) = 1
263 call HYPRE_SStructMatrixSetBoxValues(A, part, ilower, iupper,
264 + var, 1, stencil_indices, values, ierr)
265 c values above our box
266 ilower(1) = -4
267 ilower(2) = 2
268 iupper(1) = -2
269 iupper(2) = 2
270 stencil_indices(1) = 4
271 call HYPRE_SStructMatrixSetBoxValues(A, part, ilower, iupper,
272 + var, 1, stencil_indices, values, ierr)
273
274 else if (myid .eq. 1) then
275
276 c values below our box
277 ilower(1) = -1
278 ilower(2) = 0
279 iupper(1) = 2
280 iupper(2) = 0
281 stencil_indices(1) = 3
282 call HYPRE_SStructMatrixSetBoxValues(A, part, ilower, iupper,
283 + var, 1, stencil_indices, values, ierr)
284 c values to the right of our box
285 ilower(1) = 2
286 ilower(2) = 0
287 iupper(1) = 2
288 iupper(2) = 4
289 stencil_indices(1) = 2
290 call HYPRE_SStructMatrixSetBoxValues(A, part, ilower, iupper,
291 + var, 1, stencil_indices, values, ierr)
292 c values above our box
293 ilower(1) = -1
294 ilower(2) = 4
295 iupper(1) = 2
296 iupper(2) = 4
297 stencil_indices(1) = 4
298 call HYPRE_SStructMatrixSetBoxValues(A, part, ilower, iupper,
299 + var, 1, stencil_indices, values, ierr)
300 c values to the left of our box
301 c (that do not border the other box on proc. 0)
302 ilower(1) = -1
303 ilower(2) = 3
304 iupper(1) = -1
305 iupper(2) = 4
306 stencil_indices(1) = 1
307 call HYPRE_SStructMatrixSetBoxValues(A, part, ilower, iupper,
308 + var, 1, stencil_indices, values, ierr)
309
310 endif
311
312 c This is a collective call finalizing the matrix assembly
313 call HYPRE_SStructMatrixAssemble(A, ierr)
314
315 c matfile = 'ex12f.out'
316 c matfile(10:10) = char(0)
317 c call HYPRE_SStructMatrixPrint(matfile, A, 0, ierr)
318
319 c Create an empty vector object
320 call HYPRE_SStructVectorCreate(MPI_COMM_WORLD, grid, b, ierr)
321 call HYPRE_SStructVectorCreate(MPI_COMM_WORLD, grid, x, ierr)
322
323 c As with the matrix, set the appropriate object type for the vectors
324 call HYPRE_SStructVectorSetObjectTyp(b, object_type, ierr)
325 call HYPRE_SStructVectorSetObjectTyp(x, object_type, ierr)
326
327 c Indicate that the vector coefficients are ready to be set
328 call HYPRE_SStructVectorInitialize(b, ierr)
329 call HYPRE_SStructVectorInitialize(x, ierr)
330
331 c Set the vector coefficients. Again, note that the ilower values
332 c are different from those used in ex1, and some of the values are
333 c set on both processors.
334
335 if (myid .eq. 0) then
336
337 ilower(1) = -4
338 ilower(2) = 0
339 iupper(1) = -1
340 iupper(2) = 2
341
342 do i = 1, 12
343 values(i) = 1.0
344 enddo
345 call HYPRE_SStructVectorSetBoxValues(b, part, ilower, iupper,
346 + var, values, ierr)
347 do i = 1, 12
348 values(i) = 0.0
349 enddo
350 call HYPRE_SStructVectorSetBoxValues(x, part, ilower, iupper,
351 + var, values, ierr)
352
353 else if (myid .eq. 1) then
354
355 ilower(1) = 0
356 ilower(2) = 1
357 iupper(1) = 2
358 iupper(2) = 4
359
360 do i = 1, 20
361 values(i) = 1.0
362 enddo
363 call HYPRE_SStructVectorSetBoxValues(b, part, ilower, iupper,
364 + var, values, ierr)
365 do i = 1, 20
366 values(i) = 0.0
367 enddo
368 call HYPRE_SStructVectorSetBoxValues(x, part, ilower, iupper,
369 + var, values, ierr)
370
371 endif
372
373 c This is a collective call finalizing the vector assembly
374 call HYPRE_SStructVectorAssemble(b, ierr)
375 call HYPRE_SStructVectorAssemble(x, ierr)
376
377 c-----------------------------------------------------------------------
378 c 6. Set up and use a solver (See the Reference Manual for
379 c descriptions of all of the options.)
380 c-----------------------------------------------------------------------
381
382 tol = 1.0E-6
383
384 if (precond_id .eq. 1) then
385
386 c PFMG
387
388 c Because we are using a struct solver, we need to get the object
389 c of the matrix and vectors to pass in to the struct solvers
390 call HYPRE_SStructMatrixGetObject(A, sA, ierr)
391 call HYPRE_SStructVectorGetObject(b, sb, ierr)
392 call HYPRE_SStructVectorGetObject(x, sx, ierr)
393
394 c Create an empty PCG Struct solver
395 call HYPRE_StructPCGCreate(MPI_COMM_WORLD, solver, ierr)
396 c Set PCG parameters
397 call HYPRE_StructPCGSetTol(solver, tol, ierr)
398 call HYPRE_StructPCGSetPrintLevel(solver, 2, ierr)
399 call HYPRE_StructPCGSetMaxIter(solver, 50, ierr)
400
401 c Create the Struct PFMG solver for use as a preconditioner
402 call HYPRE_StructPFMGCreate(MPI_COMM_WORLD, precond, ierr)
403 c Set PFMG parameters
404 call HYPRE_StructPFMGSetMaxIter(precond, 1, ierr)
405 call HYPRE_StructPFMGSetTol(precond, 0.0, ierr)
406 call HYPRE_StructPFMGSetZeroGuess(precond, ierr)
407 call HYPRE_StructPFMGSetNumPreRelax(precond, 2, ierr)
408 call HYPRE_StructPFMGSetNumPostRelax(precond, 2, ierr)
409 c Non-Galerkin coarse grid (more efficient for this problem)
410 call HYPRE_StructPFMGSetRAPType(precond, 1, ierr)
411 c R/B Gauss-Seidel
412 call HYPRE_StructPFMGSetRelaxType(precond, 2, ierr)
413 c Skip relaxation on some levels (more efficient for this problem)
414 call HYPRE_StructPFMGSetSkipRelax(precond, 1, ierr)
415 c Set preconditioner (PFMG = 1) and solve
416 call HYPRE_StructPCGSetPrecond(solver, 1, precond, ierr)
417 call HYPRE_StructPCGSetup(solver, sA, sb, sx, ierr)
418 call HYPRE_StructPCGSolve(solver, sA, sb, sx, ierr)
419
420 c Free memory
421 call HYPRE_StructPCGDestroy(solver, ierr)
422 call HYPRE_StructPFMGDestroy(precond, ierr)
423
424 else if (precond_id .eq. 2) then
425
426 c BoomerAMG
427
428 c Because we are using a struct solver, we need to get the object
429 c of the matrix and vectors to pass in to the struct solvers
430 call HYPRE_SStructMatrixGetObject(A, parA, ierr)
431 call HYPRE_SStructVectorGetObject(b, parb, ierr)
432 call HYPRE_SStructVectorGetObject(x, parx, ierr)
433
434 c Create an empty PCG Struct solver
435 call HYPRE_ParCSRPCGCreate(MPI_COMM_WORLD, solver, ierr)
436 c Set PCG parameters
437 call HYPRE_ParCSRPCGSetTol(solver, tol, ierr)
438 call HYPRE_ParCSRPCGSetPrintLevel(solver, 2, ierr)
439 call HYPRE_ParCSRPCGSetMaxIter(solver, 50, ierr)
440
441 c Create the BoomerAMG solver for use as a preconditioner
442 call HYPRE_BoomerAMGCreate(precond, ierr)
443 c Set BoomerAMG parameters
444 call HYPRE_BoomerAMGSetMaxIter(precond, 1, ierr)
445 call HYPRE_BoomerAMGSetTol(precond, 0.0, ierr)
446 c Print amg solution info
447 call HYPRE_BoomerAMGSetPrintLevel(precond, 1, ierr)
448 call HYPRE_BoomerAMGSetCoarsenType(precond, 6, ierr)
449 c Sym G.S./Jacobi hybrid
450 call HYPRE_BoomerAMGSetRelaxType(precond, 6, ierr)
451 call HYPRE_BoomerAMGSetNumSweeps(precond, 1, ierr)
452 c Set preconditioner (BoomerAMG = 2) and solve
453 call HYPRE_ParCSRPCGSetPrecond(solver, 2, precond, ierr)
454 call HYPRE_ParCSRPCGSetup(solver, parA, parb, parx, ierr)
455 call HYPRE_ParCSRPCGSolve(solver, parA, parb, parx, ierr)
456
457 c Free memory
458 call HYPRE_ParCSRPCGDestroy(solver, ierr)
459 call HYPRE_BoomerAMGDestroy(precond, ierr)
460
461 endif
462
463 c Free memory
464 call HYPRE_SStructGridDestroy(grid, ierr)
465 call HYPRE_SStructStencilDestroy(stencil, ierr)
466 call HYPRE_SStructGraphDestroy(graph, ierr)
467 call HYPRE_SStructMatrixDestroy(A, ierr)
468 call HYPRE_SStructVectorDestroy(b, ierr)
469 call HYPRE_SStructVectorDestroy(x, ierr)
470
471 c Finalize MPI
472 call MPI_Finalize(ierr)
473
474 stop
475 end
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