1 /* Copyright (c) 2014-2020. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
8 #include "smpi_comm.hpp"
9 #include "smpi_topo.hpp"
10 #include "xbt/sysdep.h"
14 /* static functions */
15 static int assignnodes(int ndim, int nfactor, const int* pfacts, int** pdims);
16 static int getfactors(int num, int *nfators, int **factors);
22 void Topo::setComm(MPI_Comm comm)
24 xbt_assert(not comm_);
30 /*******************************************************************************
31 * Cartesian topologies
32 ******************************************************************************/
34 Topo_Cart::Topo_Cart(int ndims) : ndims_(ndims), dims_(ndims), periodic_(ndims), position_(ndims)
38 /* reorder is ignored, don't know what would be the consequences of a dumb reordering but neither do I see the point of
40 Topo_Cart::Topo_Cart(MPI_Comm comm_old, int ndims, const int dims[], const int periods[], int /*reorder*/, MPI_Comm* comm_cart)
46 int rank = comm_old->rank();
50 for (int i = 0 ; i < ndims ; i++) {
54 if(comm_cart != nullptr)
55 *comm_cart = MPI_COMM_NULL;
61 // FIXME : code duplication... See coords
63 for (int i=0; i<ndims; i++) {
65 periodic_[i] = periods[i];
66 nranks = nranks / dims[i];
67 /* FIXME: nranks could be zero (?) */
68 position_[i] = rank / nranks;
72 if(comm_cart != nullptr){
73 oldGroup = comm_old->group();
74 newGroup = new Group(newSize);
75 for (int i = 0 ; i < newSize ; i++) {
76 newGroup->set_mapping(oldGroup->actor(i), i);
78 *comm_cart = new Comm(newGroup, this);
81 if(comm_cart != nullptr){
83 MPI_Group group = new Group(MPI_COMM_SELF->group());
84 *comm_cart = new Comm(group, this);
86 *comm_cart = MPI_COMM_NULL;
90 if(comm_cart != nullptr)
94 Topo_Cart* Topo_Cart::sub(const int remain_dims[], MPI_Comm *newcomm) {
95 int oldNDims = ndims_;
96 int *newDims = nullptr;
97 int *newPeriodic = nullptr;
99 if (remain_dims == nullptr && oldNDims != 0) {
103 for (int i = 0 ; i < oldNDims ; i++) {
109 newDims = new int[newNDims];
110 newPeriodic = new int[newNDims];
112 // that should not segfault
114 for (int i = 0 ; j < newNDims ; i++) {
116 newDims[j] =dims_[i];
117 newPeriodic[j] =periodic_[i];
123 //split into several communicators
125 for (int i = 0; i < oldNDims; i++) {
126 if (not remain_dims[i]) {
127 color = (color * dims_[i] + position_[i]);
132 res = new Topo_Cart(getComm(), newNDims, newDims, newPeriodic, 0, newcomm);
134 *newcomm = getComm()->split(color, getComm()->rank());
135 res = new Topo_Cart(getComm(), newNDims, newDims, newPeriodic, 0, nullptr);
136 res->setComm(*newcomm);
139 delete[] newPeriodic;
143 int Topo_Cart::coords(int rank, int /*maxdims*/, int coords[])
145 int nnodes = nnodes_;
146 for (int i = 0; i< ndims_; i++ ) {
147 nnodes = nnodes /dims_[i];
148 coords[i] = rank / nnodes;
149 rank = rank % nnodes;
154 int Topo_Cart::get(int maxdims, int* dims, int* periods, int* coords) {
155 int ndims=ndims_ < maxdims ?ndims_ : maxdims;
156 for(int i = 0 ; i < ndims ; i++) {
158 periods[i] =periodic_[i];
159 coords[i] =position_[i];
164 int Topo_Cart::rank(const int* coords, int* rank) {
169 for (int i=ndims-1; i >=0; i-- ) {
170 int coord = coords[i];
172 /* The user can give us whatever coordinates he wants. If one of them is out of range, either this dimension is
173 * periodic, and we consider the equivalent coordinate inside the bounds, or it's not and then it's an error
175 if (coord >=dims_[i]) {
177 coord = coord %dims_[i];
179 // Should I do that ?
183 } else if (coord < 0) {
185 coord = coord %dims_[i];
187 coord =dims_[i] + coord;
194 *rank += multiplier * coord;
195 multiplier *=dims_[i];
200 int Topo_Cart::shift(int direction, int disp, int* rank_source, int* rank_dest)
205 if (ndims_ < direction) {
209 int* position = new int[ndims_];
210 this->coords(getComm()->rank(), ndims_, position);
211 position[direction] += disp;
213 if(position[direction] < 0 ||
214 position[direction] >=dims_[direction]) {
215 if(periodic_[direction]) {
216 position[direction] %=dims_[direction];
217 this->rank(position, rank_dest);
219 *rank_dest = MPI_PROC_NULL;
222 this->rank(position, rank_dest);
225 position[direction] = position_[direction] - disp;
226 if(position[direction] < 0 || position[direction] >=dims_[direction]) {
227 if(periodic_[direction]) {
228 position[direction] %=dims_[direction];
229 this->rank(position, rank_source);
231 *rank_source = MPI_PROC_NULL;
234 this->rank(position, rank_source);
240 int Topo_Cart::dim_get(int *ndims) {
245 // Everything below has been taken from ompi, but could be easily rewritten (and partially was to follow sonar rules).
248 * Copyright (c) 2004-2007 The Trustees of Indiana University and Indiana
249 * University Research and Technology
250 * Corporation. All rights reserved.
251 * Copyright (c) 2004-2005 The University of Tennessee and The University
252 * of Tennessee Research Foundation. All rights
254 * Copyright (c) 2004-2014 High Performance Computing Center Stuttgart,
255 * University of Stuttgart. All rights reserved.
256 * Copyright (c) 2004-2005 The Regents of the University of California.
257 * All rights reserved.
258 * Copyright (c) 2012 Los Alamos National Security, LLC. All rights
260 * Copyright (c) 2014 Intel, Inc. All rights reserved
263 * Additional copyrights may follow
269 * This is a utility function, no need to have anything in the lower layer for this at all
271 int Topo_Cart::Dims_create(int nnodes, int ndims, int dims[])
273 /* Get # of free-to-be-assigned processes and # of free dimensions */
274 int freeprocs = nnodes;
277 for (int i = 0; i < ndims; ++i) {
280 } else if ((*p < 0) || ((nnodes % *p) != 0)) {
290 if (freeprocs == 1) {
296 if (freeprocs == 1) {
297 for (int i = 0; i < ndims; ++i) {
306 /* Factor the number of free processes */
309 int err = getfactors(freeprocs, &nfactors, &factors);
310 if (MPI_SUCCESS != err)
313 /* Assign free processes to free dimensions */
315 err = assignnodes(freedims, nfactors, factors, &procs);
316 if (MPI_SUCCESS != err)
319 /* Return assignment results */
321 for (int i = 0; i < ndims; ++i) {
341 * Function: - assign processes to dimensions
342 * - get "best-balanced" grid
343 * - greedy bin-packing algorithm used
344 * - sort dimensions in decreasing order
345 * - dimensions array dynamically allocated
346 * Accepts: - # of dimensions
347 * - # of prime factors
348 * - array of prime factors
349 * - ptr to array of dimensions (returned value)
350 * Returns: - 0 or ERROR
352 static int assignnodes(int ndim, int nfactor, const int* pfacts, int** pdims)
360 /* Allocate and initialize the bins */
361 int *bins = new int[ndim];
366 for (int i = 0 ; i < ndim; ++i) {
370 /* Loop assigning factors from the highest to the lowest */
371 for (int j = nfactor - 1; j >= 0; --j) {
373 /* Assign a factor to the smallest bin */
376 for (int i = 1; i < ndim; ++i) {
385 /* Sort dimensions in decreasing order (O(n^2) for now) */
387 for (int i = 0; i < ndim - 1; ++i) {
389 for (int j = i + 1; j < ndim; ++j) {
406 * Function: - factorize a number
409 * - array of prime factors
410 * Returns: - MPI_SUCCESS or ERROR
412 static int getfactors(int num, int *nfactors, int **factors) {
415 (*factors) = nullptr;
418 /* Allocate the array of prime factors which cannot exceed log_2(num) entries */
419 int sqrtnum = ceil(sqrt(double(num)));
420 int size = ceil(log(double(num)) / log(2.0));
421 *factors = new int[size];
424 /* determine all occurrences of factor 2 */
425 while((num % 2) == 0) {
429 /* determine all occurrences of uneven prime numbers up to sqrt(num) */
430 for(int d = 3; (num > 1) && (d < sqrtnum); d += 2) {
431 while((num % d) == 0) {
436 /* as we looped only up to sqrt(num) one factor > sqrt(num) may be left over */
438 (*factors)[i++] = num;