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/*
* $Id: rng64.c,v 1.7 2008/03/21 17:38:39 jms Exp $
*
* This software contains proprietary and confidential information of Gradient
* Systems Inc. By accepting transfer of this copy, Recipient agrees
* to retain this software in confidence, to prevent disclosure to others, and
* to make no use of this software other than that for which it was delivered.
* This is an unpublished copyright work Gradient Systems, Inc. Execpt as
* permitted by federal law, 17 USC 117, copying is strictly prohibited.
*
* Gradient Systems Inc. CONFIDENTIAL - (Gradient Systems Inc. Confidential
* when combined with the aggregated modules for this product)
* OBJECT CODE ONLY SOURCE MATERIALS
* (C) COPYRIGHT Gradient Systems Inc. 2003
*
* All Rights Reserved
* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF GRADIENT SYSTEMS, INC.
* The copyright notice above does not evidence any
* actual or intended publication of such source code.
*
* Revision History
* ===================
* $Log: rng64.c,v $
* Revision 1.7 2008/03/21 17:38:39 jms
* changes for 2.6.3
*
* Revision 1.6 2006/04/26 23:20:05 jms
* Data type clenaup for qgen
*
* Revision 1.5 2006/03/08 21:25:27 jms
* change to RNG64 to address overflow/underflow issues
*
* Revision 1.4 2005/10/25 17:26:38 jms
* check in integration between microsoft changes and baseline code
*
* Revision 1.3 2005/03/04 19:48:39 jms
* Changes from Doug Johnson to address very large scale factors
*
* Revision 1.2 2005/01/03 20:08:59 jms
* change line terminations
*
* Revision 1.1.1.1 2004/11/24 23:31:47 jms
* re-establish external server
*
* Revision 1.2 2004/02/18 16:45:30 jms
* remove C++ style comments for AIX compiler
*
* Revision 1.1.1.1 2003/08/08 21:57:34 jms
* recreation after CVS crash
*
* Revision 1.1 2003/08/08 21:57:34 jms
* first integration of rng64 for o_custkey and l_partkey
*
*/
#include "config.h"
#include "dss.h"
#include <stdio.h>
#include <stdlib.h>
#include "rng64.h"
extern double dM;
extern seed_t Seed[];
void
dss_random64(DSS_HUGE *tgt, DSS_HUGE nLow, DSS_HUGE nHigh, long nStream)
{
DSS_HUGE nTemp;
if (nStream < 0 || nStream > MAX_STREAM)
nStream = 0;
if (nLow > nHigh)
{
nTemp = nLow;
nLow = nHigh;
nHigh = nTemp;
}
Seed[nStream].value = NextRand64(Seed[nStream].value);
nTemp = Seed[nStream].value;
if (nTemp < 0)
nTemp = -nTemp;
nTemp %= (nHigh - nLow + 1);
*tgt = nLow + nTemp;
Seed[nStream].usage += 1;
#ifdef RNG_TEST
Seed[nStream].nCalls += 1;
#endif
return;
}
DSS_HUGE
NextRand64(DSS_HUGE nSeed){
DSS_HUGE a = (unsigned DSS_HUGE) RNG_A;
DSS_HUGE c = (unsigned DSS_HUGE) RNG_C;
nSeed = (nSeed * a + c); /* implicitely truncated to 64bits */
return (nSeed);
}
DSS_HUGE AdvanceRand64( DSS_HUGE nSeed,
DSS_HUGE nCount) {
unsigned DSS_HUGE a = RNG_A ;
unsigned DSS_HUGE c = RNG_C ;
int nBit;
unsigned DSS_HUGE Apow=a, Dsum=c;
/* if nothing to do, do nothing ! */
if( nCount == 0 ) return nSeed;
/* Recursively compute X(n) = A * X(n-1) + C */
/* */
/* explicitely: */
/* X(n) = A^n * X(0) + { A^(n-1) + A^(n-2) + ... A + 1 } * C */
/* */
/* we write this as: */
/* X(n) = Apow(n) * X(0) + Dsum(n) * C */
/* */
/* we use the following relations: */
/* Apow(n) = A^(n%2)*Apow(n/2)*Apow(n/2) */
/* Dsum(n) = (n%2)*Apow(n/2)*Apow(n/2) + (Apow(n/2) + 1) * Dsum(n/2) */
/* */
/* first get the highest non-zero bit */
for( nBit = 0; (nCount >> nBit) != RNG_C ; nBit ++){}
/* go 1 bit at the time */
while( --nBit >= 0 ) {
Dsum *= (Apow + 1);
Apow = Apow * Apow;
if( ((nCount >> nBit) % 2) == 1 ) { /* odd value */
Dsum += Apow;
Apow *= a;
}
}
nSeed = nSeed * Apow + Dsum * c;
return nSeed;
}