diff src/fftw-3.3.5/mpi/transpose-pairwise.c @ 42:2cd0e3b3e1fd

Current fftw source

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/fftw-3.3.5/mpi/transpose-pairwise.c	Tue Oct 18 13:40:26 2016 +0100
@@ -0,0 +1,487 @@
+/*
+ * Copyright (c) 2003, 2007-14 Matteo Frigo
+ * Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+/* Distributed transposes using a sequence of carefully scheduled
+   pairwise exchanges.  This has the advantage that it can be done
+   in-place, or out-of-place while preserving the input, using buffer
+   space proportional to the local size divided by the number of
+   processes (i.e. to the total array size divided by the number of
+   processes squared). */
+
+#include "mpi-transpose.h"
+#include <string.h>
+
+typedef struct {
+     solver super;
+     int preserve_input; /* preserve input even if DESTROY_INPUT was passed */
+} S;
+
+typedef struct {
+     plan_mpi_transpose super;
+
+     plan *cld1, *cld2, *cld2rest, *cld3;
+     INT rest_Ioff, rest_Ooff;
+     
+     int n_pes, my_pe, *sched;
+     INT *send_block_sizes, *send_block_offsets;
+     INT *recv_block_sizes, *recv_block_offsets;
+     MPI_Comm comm;
+     int preserve_input;
+} P;
+
+static void transpose_chunks(int *sched, int n_pes, int my_pe,
+			     INT *sbs, INT *sbo, INT *rbs, INT *rbo,
+			     MPI_Comm comm,
+			     R *I, R *O)
+{
+     if (sched) {
+	  int i;
+	  MPI_Status status;
+
+	  /* TODO: explore non-synchronous send/recv? */
+
+	  if (I == O) {
+	       R *buf = (R*) MALLOC(sizeof(R) * sbs[0], BUFFERS);
+	       
+	       for (i = 0; i < n_pes; ++i) {
+		    int pe = sched[i];
+		    if (my_pe == pe) {
+			 if (rbo[pe] != sbo[pe])
+			      memmove(O + rbo[pe], O + sbo[pe],
+				      sbs[pe] * sizeof(R));
+		    }
+		    else {
+			 memcpy(buf, O + sbo[pe], sbs[pe] * sizeof(R));
+			 MPI_Sendrecv(buf, (int) (sbs[pe]), FFTW_MPI_TYPE,
+				      pe, (my_pe * n_pes + pe) & 0xffff,
+				      O + rbo[pe], (int) (rbs[pe]),
+				      FFTW_MPI_TYPE,
+				      pe, (pe * n_pes + my_pe) & 0xffff,
+				      comm, &status);
+		    }
+	       }
+
+	       X(ifree)(buf);
+	  }
+	  else { /* I != O */
+	       for (i = 0; i < n_pes; ++i) {
+		    int pe = sched[i];
+		    if (my_pe == pe)
+			 memcpy(O + rbo[pe], I + sbo[pe], sbs[pe] * sizeof(R));
+		    else
+			 MPI_Sendrecv(I + sbo[pe], (int) (sbs[pe]),
+				      FFTW_MPI_TYPE,
+				      pe, (my_pe * n_pes + pe) & 0xffff,
+				      O + rbo[pe], (int) (rbs[pe]),
+				      FFTW_MPI_TYPE,
+				      pe, (pe * n_pes + my_pe) & 0xffff,
+				      comm, &status);
+	       }
+	  }
+     }
+}
+
+static void apply(const plan *ego_, R *I, R *O)
+{
+     const P *ego = (const P *) ego_;
+     plan_rdft *cld1, *cld2, *cld2rest, *cld3;
+
+     /* transpose locally to get contiguous chunks */
+     cld1 = (plan_rdft *) ego->cld1;
+     if (cld1) {
+	  cld1->apply(ego->cld1, I, O);
+	  
+	  if (ego->preserve_input) I = O;
+
+	  /* transpose chunks globally */
+	  transpose_chunks(ego->sched, ego->n_pes, ego->my_pe,
+			   ego->send_block_sizes, ego->send_block_offsets,
+			   ego->recv_block_sizes, ego->recv_block_offsets,
+			   ego->comm, O, I);
+     }
+     else if (ego->preserve_input) {
+	  /* transpose chunks globally */
+	  transpose_chunks(ego->sched, ego->n_pes, ego->my_pe,
+			   ego->send_block_sizes, ego->send_block_offsets,
+			   ego->recv_block_sizes, ego->recv_block_offsets,
+			   ego->comm, I, O);
+
+	  I = O;
+     }
+     else {
+	  /* transpose chunks globally */
+	  transpose_chunks(ego->sched, ego->n_pes, ego->my_pe,
+			   ego->send_block_sizes, ego->send_block_offsets,
+			   ego->recv_block_sizes, ego->recv_block_offsets,
+			   ego->comm, I, I);
+     }
+
+     /* transpose locally, again, to get ordinary row-major;
+	this may take two transposes if the block sizes are unequal
+	(3 subplans, two of which operate on disjoint data) */
+     cld2 = (plan_rdft *) ego->cld2;
+     cld2->apply(ego->cld2, I, O);
+     cld2rest = (plan_rdft *) ego->cld2rest;
+     if (cld2rest) {
+	  cld2rest->apply(ego->cld2rest,
+			  I + ego->rest_Ioff, O + ego->rest_Ooff);
+	  cld3 = (plan_rdft *) ego->cld3;
+	  if (cld3)
+	       cld3->apply(ego->cld3, O, O);
+	  /* else TRANSPOSED_OUT is true and user wants O transposed */
+     }
+}
+
+static int applicable(const S *ego, const problem *p_,
+		      const planner *plnr)
+{
+     const problem_mpi_transpose *p = (const problem_mpi_transpose *) p_;
+     /* Note: this is *not* UGLY for out-of-place, destroy-input plans;
+	the planner often prefers transpose-pairwise to transpose-alltoall,
+	at least with LAM MPI on my machine. */
+     return (1
+	     && (!ego->preserve_input || (!NO_DESTROY_INPUTP(plnr)
+					  && p->I != p->O))
+	     && ONLY_TRANSPOSEDP(p->flags));
+}
+
+static void awake(plan *ego_, enum wakefulness wakefulness)
+{
+     P *ego = (P *) ego_;
+     X(plan_awake)(ego->cld1, wakefulness);
+     X(plan_awake)(ego->cld2, wakefulness);
+     X(plan_awake)(ego->cld2rest, wakefulness);
+     X(plan_awake)(ego->cld3, wakefulness);
+}
+
+static void destroy(plan *ego_)
+{
+     P *ego = (P *) ego_;
+     X(ifree0)(ego->sched);
+     X(ifree0)(ego->send_block_sizes);
+     MPI_Comm_free(&ego->comm);
+     X(plan_destroy_internal)(ego->cld3);
+     X(plan_destroy_internal)(ego->cld2rest);
+     X(plan_destroy_internal)(ego->cld2);
+     X(plan_destroy_internal)(ego->cld1);
+}
+
+static void print(const plan *ego_, printer *p)
+{
+     const P *ego = (const P *) ego_;
+     p->print(p, "(mpi-transpose-pairwise%s%(%p%)%(%p%)%(%p%)%(%p%))", 
+	      ego->preserve_input==2 ?"/p":"",
+	      ego->cld1, ego->cld2, ego->cld2rest, ego->cld3);
+}
+
+/* Given a process which_pe and a number of processes npes, fills
+   the array sched[npes] with a sequence of processes to communicate
+   with for a deadlock-free, optimum-overlap all-to-all communication.
+   (All processes must call this routine to get their own schedules.)
+   The schedule can be re-ordered arbitrarily as long as all processes
+   apply the same permutation to their schedules.
+
+   The algorithm here is based upon the one described in:
+       J. A. M. Schreuder, "Constructing timetables for sport
+       competitions," Mathematical Programming Study 13, pp. 58-67 (1980). 
+   In a sport competition, you have N teams and want every team to
+   play every other team in as short a time as possible (maximum overlap
+   between games).  This timetabling problem is therefore identical
+   to that of an all-to-all communications problem.  In our case, there
+   is one wrinkle: as part of the schedule, the process must do
+   some data transfer with itself (local data movement), analogous
+   to a requirement that each team "play itself" in addition to other
+   teams.  With this wrinkle, it turns out that an optimal timetable
+   (N parallel games) can be constructed for any N, not just for even
+   N as in the original problem described by Schreuder.
+*/
+static void fill1_comm_sched(int *sched, int which_pe, int npes)
+{
+     int pe, i, n, s = 0;
+     A(which_pe >= 0 && which_pe < npes);
+     if (npes % 2 == 0) {
+	  n = npes;
+	  sched[s++] = which_pe;
+     }
+     else
+	  n = npes + 1;
+     for (pe = 0; pe < n - 1; ++pe) {
+	  if (npes % 2 == 0) {
+	       if (pe == which_pe) sched[s++] = npes - 1;
+	       else if (npes - 1 == which_pe) sched[s++] = pe;
+	  }
+	  else if (pe == which_pe) sched[s++] = pe;
+
+	  if (pe != which_pe && which_pe < n - 1) {
+	       i = (pe - which_pe + (n - 1)) % (n - 1);
+	       if (i < n/2)
+		    sched[s++] = (pe + i) % (n - 1);
+	       
+	       i = (which_pe - pe + (n - 1)) % (n - 1);
+	       if (i < n/2)
+		    sched[s++] = (pe - i + (n - 1)) % (n - 1);
+	  }
+     }
+     A(s == npes);
+}
+
+/* Sort the communication schedule sched for npes so that the schedule
+   on process sortpe is ascending or descending (!ascending).  This is
+   necessary to allow in-place transposes when the problem does not
+   divide equally among the processes.  In this case there is one
+   process where the incoming blocks are bigger/smaller than the
+   outgoing blocks and thus have to be received in
+   descending/ascending order, respectively, to avoid overwriting data
+   before it is sent. */
+static void sort1_comm_sched(int *sched, int npes, int sortpe, int ascending)
+{
+     int *sortsched, i;
+     sortsched = (int *) MALLOC(npes * sizeof(int) * 2, OTHER);
+     fill1_comm_sched(sortsched, sortpe, npes);
+     if (ascending)
+	  for (i = 0; i < npes; ++i)
+	       sortsched[npes + sortsched[i]] = sched[i];
+     else
+	  for (i = 0; i < npes; ++i)
+	       sortsched[2*npes - 1 - sortsched[i]] = sched[i];
+     for (i = 0; i < npes; ++i)
+	  sched[i] = sortsched[npes + i];
+     X(ifree)(sortsched);
+}
+
+/* make the plans to do the post-MPI transpositions (shared with
+   transpose-alltoall) */
+int XM(mkplans_posttranspose)(const problem_mpi_transpose *p, planner *plnr,
+			      R *I, R *O, int my_pe,
+			      plan **cld2, plan **cld2rest, plan **cld3,
+			      INT *rest_Ioff, INT *rest_Ooff)
+{
+     INT vn = p->vn;
+     INT b = p->block;
+     INT bt = XM(block)(p->ny, p->tblock, my_pe);
+     INT nxb = p->nx / b; /* number of equal-sized blocks */
+     INT nxr = p->nx - nxb * b; /* leftover rows after equal blocks */
+
+     *cld2 = *cld2rest = *cld3 = NULL;
+     *rest_Ioff = *rest_Ooff = 0;
+
+     if (!(p->flags & TRANSPOSED_OUT) && (nxr == 0 || I != O)) {
+	  INT nx = p->nx * vn;
+	  b *= vn;
+	  *cld2 = X(mkplan_f_d)(plnr, 
+				X(mkproblem_rdft_0_d)(X(mktensor_3d)
+						      (nxb, bt * b, b,
+						       bt, b, nx,
+						       b, 1, 1),
+						      I, O),
+				0, 0, NO_SLOW);
+	  if (!*cld2) goto nada;
+
+	  if (nxr > 0) {
+	       *rest_Ioff = nxb * bt * b;
+	       *rest_Ooff = nxb * b;
+	       b = nxr * vn;
+	       *cld2rest = X(mkplan_f_d)(plnr,
+					 X(mkproblem_rdft_0_d)(X(mktensor_2d)
+							       (bt, b, nx,
+								b, 1, 1),
+							       I + *rest_Ioff,
+							       O + *rest_Ooff),
+                                        0, 0, NO_SLOW);
+               if (!*cld2rest) goto nada;
+	  }
+     }
+     else {
+	  *cld2 = X(mkplan_f_d)(plnr,
+				X(mkproblem_rdft_0_d)(
+				     X(mktensor_4d)
+				     (nxb, bt * b * vn, bt * b * vn,
+				      bt, b * vn, vn,
+				      b, vn, bt * vn,
+				      vn, 1, 1),
+				     I, O),
+				0, 0, NO_SLOW);
+	  if (!*cld2) goto nada;
+
+	  *rest_Ioff = *rest_Ooff = nxb * bt * b * vn;
+	  *cld2rest = X(mkplan_f_d)(plnr,
+				    X(mkproblem_rdft_0_d)(
+					 X(mktensor_3d)
+					 (bt, nxr * vn, vn,
+					  nxr, vn, bt * vn,
+					  vn, 1, 1),
+					 I + *rest_Ioff, O + *rest_Ooff),
+				    0, 0, NO_SLOW);
+	  if (!*cld2rest) goto nada;
+
+	  if (!(p->flags & TRANSPOSED_OUT)) {
+	       *cld3 = X(mkplan_f_d)(plnr,
+				     X(mkproblem_rdft_0_d)(
+					  X(mktensor_3d)
+					  (p->nx, bt * vn, vn,
+					   bt, vn, p->nx * vn,
+					   vn, 1, 1),
+					  O, O),
+				     0, 0, NO_SLOW);
+	       if (!*cld3) goto nada;
+	  }
+     }
+
+     return 1;
+
+nada:
+     X(plan_destroy_internal)(*cld3);
+     X(plan_destroy_internal)(*cld2rest);
+     X(plan_destroy_internal)(*cld2);
+     *cld2 = *cld2rest = *cld3 = NULL;
+     return 0;
+}
+
+static plan *mkplan(const solver *ego_, const problem *p_, planner *plnr)
+{
+     const S *ego = (const S *) ego_;
+     const problem_mpi_transpose *p;
+     P *pln;
+     plan *cld1 = 0, *cld2 = 0, *cld2rest = 0, *cld3 = 0;
+     INT b, bt, vn, rest_Ioff, rest_Ooff;
+     INT *sbs, *sbo, *rbs, *rbo;
+     int pe, my_pe, n_pes, sort_pe = -1, ascending = 1;
+     R *I, *O;
+     static const plan_adt padt = {
+          XM(transpose_solve), awake, print, destroy
+     };
+
+     UNUSED(ego);
+
+     if (!applicable(ego, p_, plnr))
+          return (plan *) 0;
+
+     p = (const problem_mpi_transpose *) p_;
+     vn = p->vn;
+     I = p->I; O = p->O;
+
+     MPI_Comm_rank(p->comm, &my_pe);
+     MPI_Comm_size(p->comm, &n_pes);
+
+     b = XM(block)(p->nx, p->block, my_pe);
+     
+     if (!(p->flags & TRANSPOSED_IN)) { /* b x ny x vn -> ny x b x vn */
+	  cld1 = X(mkplan_f_d)(plnr, 
+			       X(mkproblem_rdft_0_d)(X(mktensor_3d)
+						     (b, p->ny * vn, vn,
+						      p->ny, vn, b * vn,
+						      vn, 1, 1),
+						     I, O),
+			       0, 0, NO_SLOW);
+	  if (XM(any_true)(!cld1, p->comm)) goto nada;
+     }
+     if (ego->preserve_input || NO_DESTROY_INPUTP(plnr)) I = O;
+
+     if (XM(any_true)(!XM(mkplans_posttranspose)(p, plnr, I, O, my_pe,
+						 &cld2, &cld2rest, &cld3,
+						 &rest_Ioff, &rest_Ooff),
+		      p->comm)) goto nada;
+
+     pln = MKPLAN_MPI_TRANSPOSE(P, &padt, apply);
+
+     pln->cld1 = cld1;
+     pln->cld2 = cld2;
+     pln->cld2rest = cld2rest;
+     pln->rest_Ioff = rest_Ioff;
+     pln->rest_Ooff = rest_Ooff;
+     pln->cld3 = cld3;
+     pln->preserve_input = ego->preserve_input ? 2 : NO_DESTROY_INPUTP(plnr);
+
+     MPI_Comm_dup(p->comm, &pln->comm);
+
+     n_pes = (int) X(imax)(XM(num_blocks)(p->nx, p->block),
+			   XM(num_blocks)(p->ny, p->tblock));
+
+     /* Compute sizes/offsets of blocks to exchange between processors */
+     sbs = (INT *) MALLOC(4 * n_pes * sizeof(INT), PLANS);
+     sbo = sbs + n_pes;
+     rbs = sbo + n_pes;
+     rbo = rbs + n_pes;
+     b = XM(block)(p->nx, p->block, my_pe);
+     bt = XM(block)(p->ny, p->tblock, my_pe);
+     for (pe = 0; pe < n_pes; ++pe) {
+	  INT db, dbt; /* destination block sizes */
+	  db = XM(block)(p->nx, p->block, pe);
+	  dbt = XM(block)(p->ny, p->tblock, pe);
+
+	  sbs[pe] = b * dbt * vn;
+	  sbo[pe] = pe * (b * p->tblock) * vn;
+	  rbs[pe] = db * bt * vn;
+	  rbo[pe] = pe * (p->block * bt) * vn;
+
+	  if (db * dbt > 0 && db * p->tblock != p->block * dbt) {
+	       A(sort_pe == -1); /* only one process should need sorting */
+	       sort_pe = pe;
+	       ascending = db * p->tblock > p->block * dbt;
+	  }
+     }
+     pln->n_pes = n_pes;
+     pln->my_pe = my_pe;
+     pln->send_block_sizes = sbs;
+     pln->send_block_offsets = sbo;
+     pln->recv_block_sizes = rbs;
+     pln->recv_block_offsets = rbo;
+
+     if (my_pe >= n_pes) {
+	  pln->sched = 0; /* this process is not doing anything */
+     }
+     else {
+	  pln->sched = (int *) MALLOC(n_pes * sizeof(int), PLANS);
+	  fill1_comm_sched(pln->sched, my_pe, n_pes);
+	  if (sort_pe >= 0)
+	       sort1_comm_sched(pln->sched, n_pes, sort_pe, ascending);
+     }
+
+     X(ops_zero)(&pln->super.super.ops);
+     if (cld1) X(ops_add2)(&cld1->ops, &pln->super.super.ops);
+     if (cld2) X(ops_add2)(&cld2->ops, &pln->super.super.ops);
+     if (cld2rest) X(ops_add2)(&cld2rest->ops, &pln->super.super.ops);
+     if (cld3) X(ops_add2)(&cld3->ops, &pln->super.super.ops);
+     /* FIXME: should MPI operations be counted in "other" somehow? */
+
+     return &(pln->super.super);
+
+ nada:
+     X(plan_destroy_internal)(cld3);
+     X(plan_destroy_internal)(cld2rest);
+     X(plan_destroy_internal)(cld2);
+     X(plan_destroy_internal)(cld1);
+     return (plan *) 0;
+}
+
+static solver *mksolver(int preserve_input)
+{
+     static const solver_adt sadt = { PROBLEM_MPI_TRANSPOSE, mkplan, 0 };
+     S *slv = MKSOLVER(S, &sadt);
+     slv->preserve_input = preserve_input;
+     return &(slv->super);
+}
+
+void XM(transpose_pairwise_register)(planner *p)
+{
+     int preserve_input;
+     for (preserve_input = 0; preserve_input <= 1; ++preserve_input)
+	  REGISTER_SOLVER(p, mksolver(preserve_input));
+}