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/* ---------------------------------------------------------------------
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* -- Automatically Tuned Linear Algebra Software (ATLAS)
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* (C) Copyright 2000 All Rights Reserved
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* -- ATLAS routine -- Version 3.2 -- December 25, 2000
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* -- Suggestions, comments, bugs reports should be sent to the follo-
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* wing e-mail address: atlas@cs.utk.edu
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* Author : Antoine P. Petitet
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* University of Tennessee - Innovative Computing Laboratory
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* Knoxville TN, 37996-1301, USA.
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* ---------------------------------------------------------------------
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* -- Copyright notice and Licensing terms:
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions, and the following disclaimer in
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* the documentation and/or other materials provided with the distri-
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* 3. The name of the University, the ATLAS group, or the names of its
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* contributors may not be used to endorse or promote products deri-
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* ved from this software without specific written permission.
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY
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* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
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* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
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* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEO-
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* RY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (IN-
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* CLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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* ---------------------------------------------------------------------
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#include "atlas_ptmisc.h"
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DIM_1DSPLIT_T ATL_1dsplit
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const unsigned int NT,
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* ATL_1dsplit splits a problem dimension N within NT threads. This
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* function returns whether or not the problem size N should be split.
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* NT (input) const unsigned int
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* On entry, NT specifies the initial total number of threads.
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* On entry, N specifies the problem dimension to be split.
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* NB (input) const int
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* On entry, NB specifies the blocking factor to be used along
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* NT1 (output) unsigned int *
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* On exit, NT1 specifies the number of threads to be used for
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* the first part of the problem size N1.
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* NT2 (output) unsigned int *
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* On exit, NT2 specifies the number of threads to be used for
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* the second part of the problem size N2.
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* On exit, N1 specifies the length of the problem size to be
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* run on the NT1 threads.
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* On exit, N2 specifies the length of the problem size to be
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* run on the NT2 threads.
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* RATIO (output) double *
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* On exit, RATIO specifies the relative work distribution ratio
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* namely | ( N1 / NT1 ) - ( N2 / NT2 ) | / ( N / NT ).
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* ---------------------------------------------------------------------
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* .. Local Variables ..
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DIM_1DSPLIT_T split = Atlas1dNoSplit;
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unsigned int nt1, nt2, ntm1;
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int n1, n2, nblks, nbm1;
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* .. Executable Statements ..
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nblks = ( N + ( nbm1 = NB - 1 ) ) / NB;
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if( ( nblks < 2 ) || ( NT < 2 ) ) return( split );
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n1 = ( ( ( ( N + ( ntm1 = NT - 1 ) ) / NT ) + nbm1 ) / NB ) * NB;
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nt1 = (int)floor( ( (double)(n1) / n ) * nt + 0.5 );
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nt2 = NT - ( nt1 = Mmin( nt1, ntm1 ) );
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*RATIO = ( (double)(n1) / (double)(nt1) ) - ( (double)(n2) / (double)(nt2) );
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*RATIO = Mabs( *RATIO ) / ( n / nt );
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return( Atlas1dSplit );
added
removed
src/pthreads/misc/ATL_1dsplit.c
