ba237a9d91
Files correlati : Ricompilazione Demo : [ ] Commento : Aggiunti i sorgenti per Greenleaf Math Library (gfm.dll) git-svn-id: svn://10.65.10.50/trunk@10079 c028cbd2-c16b-5b4b-a496-9718f37d4682
100 lines
1.8 KiB
C
Executable File
100 lines
1.8 KiB
C
Executable File
/* DEC *StandardDeviation(pDst,pSrc,n)
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*
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* ARGUMENT
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* DEC *pDst;
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* DEC **pSrc;
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* int n;
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*
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* DESCRIPTION
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* Sets pDst to the standard deviation of the n DEC elements
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* of the array pSrc.
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* n <= 1 is not allowed. pDst is unchanged if an error occurs.
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*
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* SIDE EFFECTS
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* None.
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*
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* RETURNS
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* Returns pointer to the average if successful, otherwise
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* returns GM_NULL.
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*
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* POSSIBLE ERROR CODES
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*
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* GM_NULLPOINTER
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* GM_ARGVAL
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* GM_OVERFLOW
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*
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* AUTHOR
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* Jared Levy
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* Copyright (C) 1987-1990 Greenleaf Software Inc. All rights reserved.
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*
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* MODIFICATIONS
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*
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*/
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#include <stdio.h>
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#include "gm.h"
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#include "gmsystem.h"
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DEC *StandardDeviation(pDst,pSrc,n)
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DEC *pDst;
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DEC **pSrc;
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int n;
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{
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int i;
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DEC *p, dsum, *sum=&dsum, ddn, *dn=&ddn, dmean, *mean=&dmean;
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DEC ddiff, *diff=&ddiff, ddsq, *dsq=&ddsq;
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/* source must be supplied !! */
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_MacStart(GM_STNDDEV);
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if (!pSrc) {
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_MacErr(GM_NULLPOINTER);
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_MacRet(GM_NULL);
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}
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_MacOutVarD(pDst);
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if (n<=1) {
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_MacErr(GM_ARGVAL);
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_MacRet(GM_NULL);
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}
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for (i=0; i<n; i++) {
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_MacInVarD(pSrc[i]);
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}
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p = pSrc[0];
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_MacDCopy(sum, p);
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for (i=1;i<n;i++) {
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p = pSrc[i];
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(void) _AddDec80Bit(sum, sum, p);
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/* overflow impossible here since sum is 80 bits */
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}
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(void) ConvLongToDecimal(dn, (long) n);
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_DivDec80Bit(mean, sum, dn);
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(void) _Sq5UnsTo4Uns(mean);
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/* must succeed since |average| <= |largest element| */
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_MacDZero(sum);
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for (i=0;i<n;i++) {
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p = pSrc[i];
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(void) _SubDec80Bit(diff, p, mean);
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if (_MulDec80Bit(dsq, diff, diff)!=GM_SUCCESS) {
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_MacErr(GM_OVERFLOW);
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_MacRet(GM_NULL);
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}
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if (_AddDec80Bit(sum, sum, dsq)!=GM_SUCCESS) {
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_MacErr(GM_OVERFLOW);
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_MacRet(GM_NULL);
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}
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}
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(void) ConvLongToDecimal(dn, (long) (n-1));
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(void) _DivDec80Bit(mean, sum, dn);
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_SqrtDec80Bit(pDst, mean);
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(void) _Sq5UnsTo4Uns(pDst);
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_MacRet(pDst);
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}
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