! ! Parallel Sparse BLAS version 3.5 ! (C) Copyright 2006-2018 ! Salvatore Filippone ! Alfredo Buttari ! ! Redistribution and use in source and binary forms, with or without ! modification, are permitted provided that the following conditions ! are met: ! 1. Redistributions of source code must retain the above copyright ! notice, this list of conditions and the following disclaimer. ! 2. Redistributions in binary form must reproduce the above copyright ! notice, this list of conditions, and the following disclaimer in the ! documentation and/or other materials provided with the distribution. ! 3. The name of the PSBLAS group or the names of its contributors may ! not be used to endorse or promote products derived from this ! software without specific written permission. ! ! THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ! ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ! TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR ! PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PSBLAS GROUP OR ITS CONTRIBUTORS ! BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR ! CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF ! SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS ! INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN ! CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ! ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ! POSSIBILITY OF SUCH DAMAGE. ! ! ! ! ! File: psi_graph_fnd_owner.f90 ! ! Subroutine: psi_graph_fnd_owner ! Figure out who owns global indices. ! ! Arguments: ! idx(:) - integer Required indices on the calling process. ! ! iprc(:) - integer(psb_ipk_), allocatable Output: process identifiers ! for the corresponding indices ! idxmap - class(psb_indx_map). The index map ! info - integer. return code. ! ! This is the method to find out who owns a set of indices. ! In principle we could do the following: ! 1. Do an allgatherv of IDX ! 2. For each of the collected indices figure out if current proces owns it ! 3. Scatter the results ! 4. Loop through the answers ! This method is guaranteed to find the owner, unless an input index has ! an invalid value, however it could easily require too much additional space ! because each block of indices is replicated to all processes. ! Therefore the current routine takes a different approach: ! -1. Figure out a maximum size for a buffer to collect the IDX; the buffer ! should allow for at least one index from each process (i.e. min size NP); also ! check if we have an adjacency list of processes on input; ! 0. If the initial adjacency list is not empty, use psi_adj_fnd_sweep to go ! through all indices and use multiple calls to psi_adjcncy_fnd_owner ! (up to the buffer size) to see if the owning processes are in the ! initial neighbours list; ! 1. Extract a sample from IDX, up to the buffer size, and do a call ! to psi_a2a_fnd_owner. This is guaranteed to find the owners of all indices ! in the sample; ! 2. Build the list of processes that own the sample indices; these are ! (a subset of) the topological neighbours, and store the list in IDXMAP ! 3. Use psi_adj_fnd_sweep to go through all remaining indices and use ! multiple calls to psi_adjcncy_fnd_owner (up to the buffer size) ! to see if the owning processes are in the current neighbours list; ! 4. If the input indices IDX have not been exhausted, cycle to 1. ! ! Thus, we are alternating between asking all processes for a subset of indices, ! and asking a subset of processes for all the indices, ! thereby limiting the memory footprint to a predefined maximum ! (that the user can force with psb_cd_set_maxspace()). ! subroutine psi_graph_fnd_owner(idx,iprc,idxmap,info) use psb_serial_mod use psb_const_mod use psb_error_mod use psb_penv_mod use psb_realloc_mod use psb_timers_mod use psb_desc_mod, psb_protect_name => psi_graph_fnd_owner #ifdef MPI_MOD use mpi #endif implicit none #ifdef MPI_H include 'mpif.h' #endif integer(psb_lpk_), intent(in) :: idx(:) integer(psb_ipk_), allocatable, intent(out) :: iprc(:) class(psb_indx_map), intent(inout) :: idxmap integer(psb_ipk_), intent(out) :: info integer(psb_lpk_), allocatable :: tidx(:) integer(psb_ipk_), allocatable :: tprc(:), tsmpl(:), ladj(:) integer(psb_mpk_) :: icomm, minfo integer(psb_ipk_) :: i,n_row,n_col,err_act,ip,j, nsampl_out,& & nv, n_answers, nqries, nsampl_in, locr_max, ist, iend,& & nqries_max, nadj, maxspace, mxnsin, mnnsin, nsampl, nlansw integer(psb_lpk_) :: mglob, ih type(psb_ctxt_type) :: ctxt integer(psb_ipk_) :: np,me, nresp integer(psb_ipk_), parameter :: nt=4 integer(psb_ipk_) :: tmpv(4) logical, parameter :: do_timings=.false., trace=.false., debugsz=.false. integer(psb_ipk_), save :: idx_sweep0=-1, idx_loop_a2a=-1, idx_loop_neigh=-1 real(psb_dpk_) :: t0, t1, t2, t3, t4 character(len=20) :: name info = psb_success_ name = 'psi_graph_fnd_owner' call psb_erractionsave(err_act) ctxt = idxmap%get_ctxt() icomm = idxmap%get_mpic() mglob = idxmap%get_gr() n_row = idxmap%get_lr() n_col = idxmap%get_lc() if ((do_timings).and.(idx_sweep0==-1)) & & idx_sweep0 = psb_get_timer_idx("GRPH_FND_OWN: Outer sweep") if ((do_timings).and.(idx_loop_a2a==-1)) & & idx_loop_a2a = psb_get_timer_idx("GRPH_FND_OWN: Loop a2a") if ((do_timings).and.(idx_loop_neigh==-1)) & & idx_loop_neigh = psb_get_timer_idx("GRPH_FND_OWN: Loop neigh") call psb_info(ctxt, me, np) if (np == -1) then info = psb_err_context_error_ call psb_errpush(info,name) goto 9999 endif if (.not.(idxmap%is_valid())) then call psb_errpush(psb_err_from_subroutine_,name,a_err='invalid idxmap') goto 9999 end if ! ! ! nv = size(idx) call psb_realloc(nv,iprc,info) if (info == psb_success_) call psb_realloc(nv,tidx,info) if (info == psb_success_) call psb_realloc(nv,tprc,info) if (info == psb_success_) call psb_realloc(nv,tsmpl,info) if (info /= psb_success_) then call psb_errpush(psb_err_from_subroutine_,name,a_err='psb_realloc') goto 9999 end if iprc(:) = -1 ! ! Start from the adjacncy list ! call psb_safe_ab_cpy(idxmap%p_adjcncy,ladj,info) nadj = psb_size(ladj) ! This makes ladj allocated with size 0 if needed, as opposed to unallocated call psb_realloc(nadj,ladj,info) ! ! Throughout the subroutine, nqries is the number of local inquiries ! that have not been answered yet, n_answers is the number of queries ! that have been resolved. The queries/answers may be scattered ! through idx/iprc ! n_answers = 0 nqries = nv - n_answers nqries_max = nqries ! ! Choice of maxspace should be adjusted to account for a default ! "sensible" size and/or a user-specified value ! Currently: ! 1. Use psb_cd_get_max_space() ! 2. If nt*locr_max > maxspace, use nt_loc_max ! 3. Should be at least NP ! tmpv(1) = nadj tmpv(2) = nqries_max tmpv(3) = n_row tmpv(4) = psb_cd_get_maxspace() call psb_max(ctxt,tmpv) nqries_max = tmpv(2) locr_max = tmpv(3) maxspace = nt*locr_max if (tmpv(4) > nt*locr_max) maxspace = tmpv(4) maxspace = max(maxspace,np) if (trace.and.(me == 0)) write(0,*) ' Through graph_fnd_owner with maxspace:',& & maxspace, maxspace/np, nt*locr_max, psb_cd_get_maxspace() if (do_timings) call psb_tic(idx_sweep0) if ((tmpv(1) > 0).and.(tmpv(2) >0)) then ! ! Do a preliminary run on the user-defined adjacency lists ! if (debugsz) write(0,*) me,' Initial sweep on user-defined topology',nqries nsampl_in = min(nqries,max(1,(maxspace+max(1,nadj)-1))/(max(1,nadj))) if (trace.and.(me == 0)) write(0,*) ' Initial sweep on user-defined topology',& & nsampl_in call psi_adj_fnd_sweep(idx,iprc,ladj,idxmap,nsampl_in,n_answers) call idxmap%xtnd_p_adjcncy(ladj) nqries = nv - n_answers nqries_max = nqries call psb_max(ctxt,nqries_max) if (trace.and.(me == 0)) write(0,*) ' After initial sweep:',nqries_max if (debugsz) write(0,*) me,' After sweep on user-defined topology',nqries_max end if if (do_timings) call psb_toc(idx_sweep0) fnd_owner_loop: do while (nqries_max>0) if (do_timings) call psb_tic(idx_loop_a2a) if (debugsz) write(0,*) me,' fnd_owner_loop',nqries_max ! ! The basic idea of this loop is to alternate between ! searching through all processes and searching ! in the neighbourood. ! ! 1. Select a sample such that the total size is <= maxspace ! sample query is then sent to all processes ! if (trace.and.(me == 0)) write(0,*) 'Looping in graph_fnd_owner: ', nqries_max nsampl_in = nqries nsampl_in = min(max(1,(maxspace+np-1)/np),nsampl_in) ! ! Choose a sample, should it be done in this simplistic way? ! Note: nsampl_in is a hint, not an absolute, hence nsampl_out ! call psi_get_sample(1,idx,iprc,tidx,tsmpl,iend,nsampl_in,nsampl_out) nsampl = min(nsampl_out,nsampl_in) if (debugsz) write(0,*) me,' From first sampling ',nsampl_in ! ! 2. Do a search on all processes; this is supposed to find ! the owning process for all inputs; ! call psi_a2a_fnd_owner(tidx(1:nsampl),tprc,idxmap,info) if (debugsz) write(0,*) me,' From a2a_fnd_owner ',info call psi_cpy_out(iprc,tprc,tsmpl,nsampl,nlansw) if (nlansw < nsampl) then write(0,*) me,'Warning: indices not found by a2a_fnd_owner ',nlansw,nsampl end if n_answers = n_answers + nlansw nqries = nv - n_answers ! ! 3. Extract the resulting adjacency list and add it to the ! indxmap; ! ladj = tprc(1:nlansw) call psb_msort_unique(ladj,nadj) call psb_realloc(nadj,ladj,info) call idxmap%xtnd_p_adjcncy(ladj) if (do_timings) call psb_toc(idx_loop_a2a) if (do_timings) call psb_tic(idx_loop_neigh) ! ! 4. Do a complete sweep over the queries using ! the adjacency list just computed. ! Rationale: ! 1. Only ask to the neighbours; any missing entries ! will eventually be found by the a2a step; ! 2. Only use the adjacency list just recomputed: any ! currently open queries have already been tested ! on previous adjacency lists, no need to try them again. ! if (trace.and.(me == 0)) write(0,*) ' Further sweep',nsampl_in, mxnsin, mnnsin if (mxnsin>0) call psi_adj_fnd_sweep(idx,iprc,ladj,& & idxmap,nsampl_in,n_answers) nqries = nv - n_answers nqries_max = nqries call psb_max(ctxt,nqries_max) if (trace.and.(me == 0)) write(0,*) ' fnd_owner_loop remaining:',nqries_max if (do_timings) call psb_toc(idx_loop_neigh) end do fnd_owner_loop call psb_erractionrestore(err_act) return 9999 call psb_error_handler(ctxt,err_act) return contains ! ! Get a sample. ! 1. Start from entry istart; ! 2. Collect unanswered queries ! 3. Up to ns_in sample size; ! 4. Record the actual sample size; ! 5. Record where the sample stopped in case ! you need to complete a sweep through the data ! 6. For each query, record where in the original vector ! it came from; ! 7. There could be scattered answered/unanswered queries, ! so the code needs to skip existing answers; hence, the ! number of items sampled and the index where it stops ! differ. ! ! subroutine psi_get_sample(istart,idx,iprc,tidx,tsmpl,iend,ns_in,ns_out) implicit none integer(psb_lpk_), intent(in) :: idx(:) integer(psb_ipk_), intent(in) :: ns_in, iprc(:),istart integer(psb_lpk_), intent(out) :: tidx(:) integer(psb_ipk_), intent(out) :: tsmpl(:), ns_out,iend ! integer(psb_ipk_) :: nv, ns, k, ipnt nv = size(idx) ns = ns_in ! ! ns_in == 0 means that on the outside we figure there's ! nothing left, but we need to do something because the adj_sweep is ! sinchronized ! Make sure we sweep through the entire vector immediately. ! But also make sure we do not overrun tsmpl ! ns = min(ns,size(tsmpl)) ns_out = 0 ipnt = istart-1 do while(ipnt= ns) exit end do iend = ipnt end subroutine psi_get_sample subroutine psi_cpy_out(iprc,tprc,tsmpl,ns_in,ns_out) implicit none integer(psb_ipk_), intent(out) :: iprc(:) integer(psb_ipk_), intent(in) :: ns_in integer(psb_ipk_), intent(in) :: tprc(:), tsmpl(:) integer(psb_ipk_), intent(out) :: ns_out integer(psb_ipk_) :: j ns_out = 0 do j=1, ns_in if (tprc(j) /= -1) then ns_out = ns_out + 1 iprc(tsmpl(j)) = tprc(j) end if end do end subroutine psi_cpy_out subroutine psi_adj_fnd_sweep(idx,iprc,adj,idxmap,n_samples,n_answers) implicit none integer(psb_lpk_), intent(in) :: idx(:) integer(psb_ipk_), intent(in) :: n_samples integer(psb_ipk_), intent(inout) :: iprc(:), n_answers integer(psb_ipk_), intent(in) :: adj(:) class(psb_indx_map), intent(inout) :: idxmap ! type(psb_ctxt_type) :: ctxt integer(psb_ipk_) :: ipnt, ns_in, ns_out, n_rem, me, np, isw, n_reml,iend, nv integer(psb_lpk_), allocatable :: tidx(:) integer(psb_ipk_), allocatable :: tsmpl(:) ctxt = idxmap%get_ctxt() call psb_info(ctxt,me,np) call psb_realloc(n_samples,tidx,info) call psb_realloc(n_samples,tsmpl,info) ipnt = 1 isw = 1 nv = size(idx) do ! Sweep through the vector, one section at a time, ! up to N_SAMPLES samples. The sections are unpredictable, because ! the queries are scattered; hence the need for get_sample ! to tell us where the current section ends ! call psi_get_sample(ipnt,idx,iprc,tidx,tsmpl,iend,n_samples,ns_out) ns_in = min(n_samples,ns_out) ! call psi_adjcncy_fnd_owner(tidx(1:ns_in),tprc,ladj,idxmap,info) call psi_cpy_out(iprc,tprc,tsmpl,ns_in,ns_out) ! ! Update starting point of next sweep and number of remaining ! queries to check for end of loop. ! n_answers = n_answers + ns_out ipnt = iend + 1 n_reml = nv - ipnt + 1 n_rem = n_reml call psb_max(ctxt,n_rem) ! if (me == 0) write(0,*) me,' fnd_sweep Sweep ',isw,n_rem, ipnt, n_samples, n_reml isw = isw + 1 if (n_rem <= 0) exit end do ! if (me == 0) write(0,*)'adj_fnd_sweep: sweeps: ',isw end subroutine psi_adj_fnd_sweep end subroutine psi_graph_fnd_owner