root / testing / matgen / HPL_rand.c
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/*
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* -- High Performance Computing Linpack Benchmark (HPL)
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* HPL - 2.0 - September 10, 2008
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* Antoine P. Petitet
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* University of Tennessee, Knoxville
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* Innovative Computing Laboratory
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* (C) Copyright 2000-2008 All Rights Reserved
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*
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* -- Copyright notice and Licensing terms:
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*
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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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* are met:
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*
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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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*
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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 the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgement:
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* This product includes software developed at the University of
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* Tennessee, Knoxville, Innovative Computing Laboratory.
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*
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* 4. The name of the University, the name of the Laboratory, or the
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* names of its contributors may not be used to endorse or promote
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* products derived from this software without specific written
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* permission.
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*
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* -- Disclaimer:
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*
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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,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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* ---------------------------------------------------------------------
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*/
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/*
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* Include files
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*/
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#include "hpl.h" |
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#ifdef STDC_HEADERS
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double HPL_rand( void ) |
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#else
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double HPL_rand()
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#endif
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{
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/*
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* Purpose
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* =======
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*
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* HPL_rand generates the next number in the random sequence. This
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* function ensures that this number lies in the interval (-0.5, 0.5].
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*
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* The static array irand contains the information (2 integers) required
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* to generate the next number in the sequence X(n). This number is
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* computed as X(n) = (2^32 * irand[1] + irand[0]) / d - 0.5, where the
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* constant d is the largest 64 bit positive unsigned integer. The array
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* irand is then updated for the generation of the next number X(n+1)
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* in the random sequence as follows X(n+1) = a * X(n) + c. The
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* constants a and c should have been preliminarily stored in the arrays
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* ias and ics as 2 pairs of integers. The initialization of ias, ics
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* and irand is performed by the function HPL_setran.
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*
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* ---------------------------------------------------------------------
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*/
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/*
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* .. Local Variables ..
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*/
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int j[2]; |
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/* ..
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* .. Executable Statements ..
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*/
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HPL_setran( 3, j );
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/*
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* return number between -0.5 and 0.5
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*/
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return( HPL_HALF -
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(((j[0] & 65535) + ((unsigned)j[0] >> 16) * HPL_POW16) / HPL_DIVFAC * HPL_HALF + |
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(j[1] & 65535) + ((unsigned)j[1] >> 16) * HPL_POW16) / HPL_DIVFAC * HPL_HALF ); |
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/*
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* End of HPL_rand
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*/
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} |