Omit usage of pre calculated prime numbers and factorize directly.
Optimization of the MPI_Dims_create function which omits the usage of pre calculated prime numbers and factorize directly as discussed at the developer list. cmr=v1.7.5:ticket=4217:reviewer=jsquyres This commit was SVN r30695. The following Trac tickets were found above: Ticket 4217 --> https://svn.open-mpi.org/trac/ompi/ticket/4217
Этот коммит содержится в:
Christoph Niethammer
родитель
85dce869c8
Коммит
010a806a58
@ -5,7 +5,7 @@
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* Copyright (c) 2004-2005 The University of Tennessee and The University
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* of Tennessee Research Foundation. All rights
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* reserved.
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* Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
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* Copyright (c) 2004-2014 High Performance Computing Center Stuttgart,
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* University of Stuttgart. All rights reserved.
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* Copyright (c) 2004-2005 The Regents of the University of California.
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* All rights reserved.
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@ -20,6 +20,8 @@
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#include "ompi_config.h"
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#include <math.h>
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#include "ompi/mpi/c/bindings.h"
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#include "ompi/runtime/params.h"
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#include "ompi/communicator/communicator.h"
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@ -36,9 +38,8 @@
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static const char FUNC_NAME[] = "MPI_Dims_create";
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/* static functions */
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static int assignnodes(int ndim, int nfactor, int *pfacts, int *counts, int **pdims);
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static int getfactors(int num, int nprime, int *primes, int **pcounts);
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static int getprimes(int num, int *pnprime, int **pprimes);
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static int assignnodes(int ndim, int nfactor, int *pfacts,int **pdims);
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static int getfactors(int num, int *nfators, int **factors);
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/*
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@ -50,8 +51,7 @@ int MPI_Dims_create(int nnodes, int ndims, int dims[])
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int i;
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int freeprocs;
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int freedims;
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int nprimes;
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int *primes;
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int nfactors;
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int *factors;
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int *procs;
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int *p;
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@ -109,20 +109,14 @@ int MPI_Dims_create(int nnodes, int ndims, int dims[])
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return MPI_SUCCESS;
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}
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/* Compute the relevant prime numbers for factoring */
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if (MPI_SUCCESS != (err = getprimes(freeprocs, &nprimes, &primes))) {
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return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, err,
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FUNC_NAME);
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}
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/* Factor the number of free processes */
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if (MPI_SUCCESS != (err = getfactors(freeprocs, nprimes, primes, &factors))) {
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if (MPI_SUCCESS != (err = getfactors(freeprocs, &nfactors, &factors))) {
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return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, err,
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FUNC_NAME);
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}
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/* Assign free processes to free dimensions */
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if (MPI_SUCCESS != (err = assignnodes(freedims, nprimes, primes, factors, &procs))) {
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if (MPI_SUCCESS != (err = assignnodes(freedims, nfactors, factors, &procs))) {
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return OMPI_ERRHANDLER_INVOKE(MPI_COMM_WORLD, err,
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FUNC_NAME);
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}
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@ -135,7 +129,6 @@ int MPI_Dims_create(int nnodes, int ndims, int dims[])
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}
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}
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free((char *) primes);
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free((char *) factors);
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free((char *) procs);
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@ -154,12 +147,11 @@ int MPI_Dims_create(int nnodes, int ndims, int dims[])
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* Accepts: - # of dimensions
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* - # of prime factors
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* - array of prime factors
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* - array of factor counts
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* - ptr to array of dimensions (returned value)
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* Returns: - 0 or ERROR
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*/
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static int
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assignnodes(int ndim, int nfactor, int *pfacts, int *counts, int **pdims)
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assignnodes(int ndim, int nfactor, int *pfacts, int **pdims)
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{
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int *bins;
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int i, j;
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@ -185,17 +177,15 @@ assignnodes(int ndim, int nfactor, int *pfacts, int *counts, int **pdims)
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/* Loop assigning factors from the highest to the lowest */
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for (j = nfactor - 1; j >= 0; --j) {
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f = pfacts[j];
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for (n = counts[j]; n > 0; --n) {
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/* Assign a factor to the smallest bin */
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pmin = bins;
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for (i = 1, p = pmin + 1; i < ndim; ++i, ++p) {
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if (*p < *pmin) {
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pmin = p;
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}
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f = pfacts[j];
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/* Assign a factor to the smallest bin */
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pmin = bins;
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for (i = 1, p = pmin + 1; i < ndim; ++i, ++p) {
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if (*p < *pmin) {
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pmin = p;
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}
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*pmin *= f;
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}
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*pmin *= f;
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}
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/* Sort dimensions in decreasing order (O(n^2) for now) */
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@ -217,96 +207,47 @@ assignnodes(int ndim, int nfactor, int *pfacts, int *counts, int **pdims)
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*
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* Function: - factorize a number
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* Accepts: - number
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* - # of primes
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* - array of primes
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* - ptr to array of counts (returned value)
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* Returns: - 0 or ERROR
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* - # prime factors
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* - array of prime factors
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* Returns: - MPI_SUCCESS or ERROR
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*/
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static int
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getfactors(int num, int nprime, int *primes, int **pcounts)
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{
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int *counts;
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getfactors(int num, int *nfactors, int **factors) {
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int size;
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int n;
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int d;
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int i;
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int *p;
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int *c;
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if (0 >= nprime) {
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return MPI_ERR_INTERN;
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int sqrtnum;
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if(num < 2) {
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(*nfactors) = 0;
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(*factors) = NULL;
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return MPI_SUCCESS;
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}
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/* Allocate the array of prime factors which cannot exceed log_2(num) entries */
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n = num;
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sqrtnum = ceil(sqrt(num));
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size = ceil(log(num) / log(2));
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*factors = (int *) malloc((unsigned) size * sizeof(int));
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/* Allocate the factor counts array */
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counts = (int *) malloc((unsigned) nprime * sizeof(int));
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if (NULL == counts) {
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return MPI_ERR_NO_MEM;
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i = 0;
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/* determine all occurences of factor 2 */
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while((num % 2) == 0) {
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num /= 2;
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(*factors)[i++] = 2;
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}
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*pcounts = counts;
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/* Loop over the prime numbers */
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i = nprime - 1;
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p = primes + i;
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c = counts + i;
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for (; i >= 0; --i, --p, --c) {
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*c = 0;
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while ((num % *p) == 0) {
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++(*c);
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num /= *p;
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/* determine all occurences of uneven prime numbers up to sqrt(num) */
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d = 3;
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for(d = 3; (num > 1) && (d < sqrtnum); d += 2) {
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while((num % d) == 0) {
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num /= d;
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(*factors)[i++] = d;
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}
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}
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if (1 != num) {
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return MPI_ERR_INTERN;
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/* as we looped only up to sqrt(num) one factor > sqrt(num) may be left over */
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if(num != 1) {
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(*factors)[i++] = num;
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}
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(*nfactors) = i;
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return MPI_SUCCESS;
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}
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/*
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* getprimes
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*
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* Function: - get primes smaller than number
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* - array of primes dynamically allocated
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* Accepts: - number
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* - ptr # of primes (returned value)
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* - ptr array of primes (returned values)
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* Returns: - 0 or ERROR
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*/
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static int
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getprimes(int num, int *pnprime, int **pprimes) {
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int i, j;
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int n;
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int size;
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int *primes;
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/* Allocate the array of primes */
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size = (num / 2) + 1;
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primes = (int *) malloc((unsigned) size * sizeof(int));
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if (NULL == primes) {
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return MPI_ERR_NO_MEM;
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}
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*pprimes = primes;
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/* Find the prime numbers */
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i = 0;
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primes[i++] = 2;
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for (n = 3; n <= num; n += 2) {
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for (j = 1; j < i; ++j) {
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if ((n % primes[j]) == 0) {
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break;
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}
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}
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if (j == i) {
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if (i >= size) {
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return MPI_ERR_DIMS;
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}
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primes[i++] = n;
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}
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}
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*pnprime = i;
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return MPI_SUCCESS;
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}
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