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  1 c
  2 c   Example 5
  3 c
  4 c   Interface:    Linear-Algebraic (IJ), Fortran (77) version
  5 c
  6 c   Compile with: make ex5f
  7 c
  8 c   Sample run:   mpirun -np 4 ex5f
  9 c
 10 c   Description:  This example solves the 2-D
 11 c                 Laplacian problem with zero boundary conditions
 12 c                 on an nxn grid.  The number of unknowns is N=n^2.
 13 c                 The standard 5-point stencil is used, and we solve
 14 c                 for the interior nodes only.
 15 c
 16 c                 This example solves the same problem as Example 3.
 17 c                 Available solvers are AMG, PCG, and PCG with AMG,
 18 c                 and PCG with ParaSails    
 19 c
 20 c
 21 c                 Notes: for PCG, GMRES and BiCGStab, precond_id means:
 22 c                        0 - do not set up a preconditioner
 23 c                        1 - set up a ds preconditioner
 24 c                        2 - set up an amg preconditioner
 25 c                        3 - set up a pilut preconditioner
 26 c                        4 - set up a ParaSails preconditioner
 27 c
 28 
 29 
 30 
 31       program ex5f
 32 
 33 
 34       implicit none
 35 
 36       include 'mpif.h'
 37 
 38       integer    MAX_LOCAL_SIZE
 39       integer    HYPRE_PARCSR
 40 
 41       parameter  (MAX_LOCAL_SIZE=123000)
 42 
 43 c     the following is from HYPRE.c
 44       parameter  (HYPRE_PARCSR=5555)
 45 
 46       integer    ierr
 47       integer    num_procs, myid
 48       integer    local_size, extra
 49       integer    n, solver_id, print_solution, ng
 50       integer    nnz, ilower, iupper, i
 51       integer    precond_id;
 52       double precision h, h2
 53       double precision rhs_values(MAX_LOCAL_SIZE)
 54       double precision x_values(MAX_LOCAL_SIZE)
 55       integer    rows(MAX_LOCAL_SIZE)
 56       integer    cols(5)
 57       double precision values(5)
 58       integer    num_iterations
 59       double precision final_res_norm, tol
 60 
 61       integer*8  mpi_comm
 62       integer*8  parcsr_A
 63       integer*8  A
 64       integer*8  b
 65       integer*8  x
 66       integer*8  par_b
 67       integer*8  par_x
 68       integer*8  solver
 69       integer*8  precond
 70  
 71 c-----------------------------------------------------------------------
 72 c     Initialize MPI
 73 c-----------------------------------------------------------------------
 74 
 75       call MPI_INIT(ierr)
 76       call MPI_COMM_RANK(MPI_COMM_WORLD, myid, ierr)
 77       call MPI_COMM_SIZE(MPI_COMM_WORLD, num_procs, ierr)
 78       mpi_comm = MPI_COMM_WORLD
 79 
 80 c   Default problem parameters
 81       n = 33
 82       solver_id = 0
 83       print_solution  = 0
 84       tol = 1.0d-7
 85 
 86 c   The input section not implemented yet.
 87 
 88 c   Preliminaries: want at least one processor per row
 89       if ( n*n .lt. num_procs) then
 90          n = int(sqrt(real(num_procs))) + 1
 91       endif
 92 c     ng = global no. rows, h = mesh size      
 93       ng = n*n
 94       h = 1.0d0/(n+1)
 95       h2 = h*h
 96 
 97 c     Each processor knows only of its own rows - the range is denoted by ilower
 98 c     and upper.  Here we partition the rows. We account for the fact that
 99 c     N may not divide evenly by the number of processors.
100       local_size = ng/num_procs
101       extra = ng - local_size*num_procs
102 
103       ilower = local_size*myid
104       ilower = ilower + min(myid, extra)
105 
106       iupper = local_size*(myid+1)
107       iupper = iupper + min(myid+1, extra)
108       iupper = iupper - 1
109 
110 c     How many rows do I have?
111       local_size = iupper - ilower + 1
112 
113 c     Create the matrix.
114 c     Note that this is a square matrix, so we indicate the row partition
115 c     size twice (since number of rows = number of cols)
116       call HYPRE_IJMatrixCreate( mpi_comm, ilower,
117      1     iupper, ilower, iupper, A, ierr )
118 
119 
120 c     Choose a parallel csr format storage (see the User's Manual)
121       call HYPRE_IJMatrixSetObjectType( A, HYPRE_PARCSR, ierr)
122 
123 c     Initialize before setting coefficients
124       call HYPRE_IJMatrixInitialize( A, ierr)
125 
126 
127 c     Now go through my local rows and set the matrix entries.
128 c     Each row has at most 5 entries. For example, if n=3:
129 c
130 c      A = [M -I 0; -I M -I; 0 -I M]
131 c      M = [4 -1 0; -1 4 -1; 0 -1 4]
132 c
133 c     Note that here we are setting one row at a time, though
134 c     one could set all the rows together (see the User's Manual).
135 
136 
137       do i = ilower, iupper
138          nnz = 1
139          
140 
141 c        The left identity block:position i-n
142          if ( (i-n) .ge. 0 ) then
143 	    cols(nnz) = i-n
144 	    values(nnz) = -1.0d0
145 	    nnz = nnz + 1
146          endif
147 
148 c         The left -1: position i-1
149          if ( mod(i,n).ne.0 ) then
150             cols(nnz) = i-1
151             values(nnz) = -1.0d0
152             nnz = nnz + 1
153          endif
154 
155 c        Set the diagonal: position i
156          cols(nnz) = i
157          values(nnz) = 4.0d0
158          nnz = nnz + 1
159 
160 c        The right -1: position i+1
161          if ( mod((i+1),n) .ne. 0 ) then
162             cols(nnz) = i+1
163             values(nnz) = -1.0d0
164             nnz = nnz + 1
165          endif
166 
167 c        The right identity block:position i+n
168          if ((i+n) .lt. ng ) then
169             cols(nnz) = i+n
170             values(nnz) = -1.0d0
171             nnz = nnz + 1
172          endif
173 
174 c        Set the values for row i
175          call HYPRE_IJMatrixSetValues(
176      1        A, 1, nnz-1, i, cols, values, ierr)
177 
178       enddo
179 
180 
181 c     Assemble after setting the coefficients
182       call HYPRE_IJMatrixAssemble( A, ierr)
183 
184 c     Get parcsr matrix object
185       call HYPRE_IJMatrixGetObject( A, parcsr_A, ierr)
186 
187 
188 c     Create the rhs and solution
189       call HYPRE_IJVectorCreate(mpi_comm,
190      1     ilower, iupper, b, ierr )
191       call HYPRE_IJVectorSetObjectType(b, HYPRE_PARCSR, ierr)
192       call HYPRE_IJVectorInitialize(b, ierr)
193   
194       call HYPRE_IJVectorCreate(mpi_comm,
195      1     ilower, iupper, x, ierr )
196       call HYPRE_IJVectorSetObjectType(x, HYPRE_PARCSR, ierr)
197       call HYPRE_IJVectorInitialize(x, ierr)
198 
199 
200 c     Set the rhs values to h^2 and the solution to zero
201       do i = 1, local_size
202          rhs_values(i) = h2
203          x_values(i) = 0.0
204          rows(i) = ilower + i -1
205       enddo
206       call HYPRE_IJVectorSetValues(
207      1     b, local_size, rows, rhs_values, ierr )
208       call HYPRE_IJVectorSetValues(
209      1     x, local_size, rows, x_values, ierr)
210 
211 
212       call HYPRE_IJVectorAssemble( b, ierr)
213       call HYPRE_IJVectorAssemble( x, ierr)
214 
215 c get the x and b objects
216 
217       call HYPRE_IJVectorGetObject( b, par_b, ierr)
218       call HYPRE_IJVectorGetObject( x, par_x, ierr)
219 
220 
221 c     Choose a solver and solve the system
222 
223 c     AMG
224       if ( solver_id .eq. 0 ) then
225 
226 c        Create solver
227          call HYPRE_BoomerAMGCreate(solver, ierr)
228 
229 
230 c        Set some parameters (See Reference Manual for more parameters)
231 
232 c        print solve info + parameters 
233          call HYPRE_BoomerAMGSetPrintLevel(solver, 3, ierr)  
234 c        Falgout coarsening
235          call HYPRE_BoomerAMGSetCoarsenType(solver, 6, ierr) 
236 c        G-S/Jacobi hybrid relaxation 
237          call HYPRE_BoomerAMGSetRelaxType(solver, 3, ierr)     
238 c        Sweeeps on each level
239          call HYPRE_BoomerAMGSetNumSweeps(solver, 1, ierr)  
240 c         maximum number of levels 
241          call HYPRE_BoomerAMGSetMaxLevels(solver, 20, ierr) 
242 c        conv. tolerance
243          call HYPRE_BoomerAMGSetTol(solver, 1.0d-7, ierr)    
244 
245 c        Now setup and solve!
246          call HYPRE_BoomerAMGSetup(
247      1        solver, parcsr_A, par_b, par_x, ierr )
248          call HYPRE_BoomerAMGSolve(
249      1        solver, parcsr_A, par_b, par_x, ierr )
250 
251 
252 c        Run info - needed logging turned on 
253          call HYPRE_BoomerAMGGetNumIterations(solver, num_iterations, 
254      1        ierr)
255          call HYPRE_BoomerAMGGetFinalReltvRes(solver, final_res_norm,
256      1        ierr)
257 
258 
259          if (myid .eq. 0) then
260             print *
261             print *, "Iterations = ", num_iterations
262             print *, "Final Relative Residual Norm = ", final_res_norm
263             print *
264          endif
265          
266 c        Destroy solver
267          call HYPRE_BoomerAMGDestroy( solver, ierr )
268 
269 c     PCG (with DS)
270       elseif (solver_id .eq. 50) then  
271          
272 
273 c        Create solver
274          call HYPRE_ParCSRPCGCreate(MPI_COMM_WORLD, solver, ierr)
275 
276 c        Set some parameters (See Reference Manual for more parameters) 
277          call HYPRE_ParCSRPCGSetMaxIter(solver, 1000, ierr)
278          call HYPRE_ParCSRPCGSetTol(solver, 1.0d-7, ierr)
279          call HYPRE_ParCSRPCGSetTwoNorm(solver, 1, ierr)
280          call HYPRE_ParCSRPCGSetPrintLevel(solver, 2, ierr)
281          call HYPRE_ParCSRPCGSetLogging(solver, 1, ierr)
282 
283 c        set ds (diagonal scaling) as the pcg preconditioner 
284          precond_id = 1
285          call HYPRE_ParCSRPCGSetPrecond(solver, precond_id,
286      1        precond, ierr)
287 
288 
289 
290 c        Now setup and solve!
291          call HYPRE_ParCSRPCGSetup(solver, parcsr_A, par_b,
292      &                            par_x, ierr)
293          call HYPRE_ParCSRPCGSolve(solver, parcsr_A, par_b,
294      &                            par_x, ierr)
295 
296 
297 c        Run info - needed logging turned on 
298 
299         call HYPRE_ParCSRPCGGetNumIterations(solver, num_iterations,
300      &                                       ierr)
301         call HYPRE_ParCSRPCGGetFinalRelative(solver, final_res_norm,
302      &                                       ierr)
303 
304        if (myid .eq. 0) then
305             print *
306             print *, "Iterations = ", num_iterations
307             print *, "Final Relative Residual Norm = ", final_res_norm
308             print *
309          endif
310 
311 c       Destroy solver 
312         call HYPRE_ParCSRPCGDestroy(solver, ierr)
313 
314 
315 c     PCG with AMG preconditioner
316       elseif (solver_id == 1) then
317      
318 c        Create solver
319          call HYPRE_ParCSRPCGCreate(MPI_COMM_WORLD, solver, ierr)
320 
321 c        Set some parameters (See Reference Manual for more parameters) 
322          call HYPRE_ParCSRPCGSetMaxIter(solver, 1000, ierr)
323          call HYPRE_ParCSRPCGSetTol(solver, 1.0d-7, ierr)
324          call HYPRE_ParCSRPCGSetTwoNorm(solver, 1, ierr)
325          call HYPRE_ParCSRPCGSetPrintLevel(solver, 2, ierr)
326          call HYPRE_ParCSRPCGSetLogging(solver, 1, ierr)
327 
328 c        Now set up the AMG preconditioner and specify any parameters
329 
330          call HYPRE_BoomerAMGCreate(precond, ierr)
331 
332 
333 c        Set some parameters (See Reference Manual for more parameters)
334 
335 c        print less solver info since a preconditioner
336          call HYPRE_BoomerAMGSetPrintLevel(precond, 1, ierr); 
337 c        Falgout coarsening
338          call HYPRE_BoomerAMGSetCoarsenType(precond, 6, ierr) 
339 c        SYMMETRIC G-S/Jacobi hybrid relaxation 
340          call HYPRE_BoomerAMGSetRelaxType(precond, 6, ierr)     
341 c        Sweeeps on each level
342          call HYPRE_BoomerAMGSetNumSweeps(precond, 1, ierr)  
343 c        conv. tolerance
344          call HYPRE_BoomerAMGSetTol(precond, 0.0d0, ierr)     
345 c        do only one iteration! 
346          call HYPRE_BoomerAMGSetMaxIter(precond, 1, ierr)
347 
348 c        set amg as the pcg preconditioner
349          precond_id = 2
350          call HYPRE_ParCSRPCGSetPrecond(solver, precond_id,
351      1        precond, ierr)
352 
353 
354 c        Now setup and solve!
355          call HYPRE_ParCSRPCGSetup(solver, parcsr_A, par_b,
356      1                            par_x, ierr)
357          call HYPRE_ParCSRPCGSolve(solver, parcsr_A, par_b,
358      1                            par_x, ierr)
359 
360 
361 c        Run info - needed logging turned on 
362 
363         call HYPRE_ParCSRPCGGetNumIterations(solver, num_iterations,
364      1                                       ierr)
365         call HYPRE_ParCSRPCGGetFinalRelative(solver, final_res_norm,
366      1                                       ierr)
367 
368        if (myid .eq. 0) then
369             print *
370             print *, "Iterations = ", num_iterations
371             print *, "Final Relative Residual Norm = ", final_res_norm
372             print *
373          endif
374 
375 c       Destroy precond and solver
376 
377         call HYPRE_BoomerAMGDestroy(precond, ierr )
378         call HYPRE_ParCSRPCGDestroy(solver, ierr)
379 
380 c     PCG with ParaSails
381       elseif (solver_id .eq. 8) then
382 
383 c        Create solver
384          call HYPRE_ParCSRPCGCreate(MPI_COMM_WORLD, solver, ierr)
385 
386 c        Set some parameters (See Reference Manual for more parameters) 
387          call HYPRE_ParCSRPCGSetMaxIter(solver, 1000, ierr)
388          call HYPRE_ParCSRPCGSetTol(solver, 1.0d-7, ierr)
389          call HYPRE_ParCSRPCGSetTwoNorm(solver, 1, ierr)
390          call HYPRE_ParCSRPCGSetPrintLevel(solver, 2, ierr)
391          call HYPRE_ParCSRPCGSetLogging(solver, 1, ierr)
392 
393 c        Now set up the Parasails preconditioner and specify any parameters
394          call HYPRE_ParaSailsCreate(MPI_COMM_WORLD, precond,ierr)
395          call HYPRE_ParaSailsSetParams(precond, 0.1d0, 1, ierr)
396          call HYPRE_ParaSailsSetFilter(precond, 0.05d0, ierr)
397          call HYPRE_ParaSailsSetSym(precond, 1)
398          call HYPRE_ParaSailsSetLogging(precond, 3, ierr)
399 
400 c        set parsails as the pcg preconditioner
401          precond_id = 4
402          call HYPRE_ParCSRPCGSetPrecond(solver, precond_id,
403      1        precond, ierr)
404 
405 
406 c        Now setup and solve!
407          call HYPRE_ParCSRPCGSetup(solver, parcsr_A, par_b,
408      1                            par_x, ierr)
409          call HYPRE_ParCSRPCGSolve(solver, parcsr_A, par_b,
410      1                            par_x, ierr)
411 
412 
413 c        Run info - needed logging turned on 
414 
415         call HYPRE_ParCSRPCGGetNumIterations(solver, num_iterations,
416      1                                       ierr)
417         call HYPRE_ParCSRPCGGetFinalRelative(solver, final_res_norm,
418      1                                       ierr)
419 
420        if (myid .eq. 0) then
421             print *
422             print *, "Iterations = ", num_iterations
423             print *, "Final Relative Residual Norm = ", final_res_norm
424             print *
425          endif
426 
427 c       Destroy precond and solver
428 
429         call HYPRE_ParaSailsDestroy(precond, ierr )
430         call HYPRE_ParCSRPCGDestroy(solver, ierr)
431 
432       else
433          if (myid .eq. 0) then 
434            print *,'Invalid solver id specified'
435            stop
436          endif  
437       endif
438 
439 
440 
441 c     Print the solution
442       if ( print_solution .ne. 0 ) then
443          call HYPRE_IJVectorPrint( x, "ij.out.x", ierr)
444       endif
445 
446 c     Clean up
447 
448       call HYPRE_IJMatrixDestroy(A, ierr)
449       call HYPRE_IJVectorDestroy(b, ierr)
450       call HYPRE_IJVectorDestroy(x, ierr)
451 
452 
453 c     Finalize MPI
454       call MPI_Finalize(ierr)
455 
456       stop
457       end


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