91 lines
1.6 KiB
C
91 lines
1.6 KiB
C
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/* DEC *WeightedMean(pDst,pSrc,weight,n)
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*
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* ARGUMENT
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* DEC *pDst;
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* DEC **pSrc, **weight;
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* int n;
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*
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* DESCRIPTION
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* Sets pDst to the weighted mean of the n DEC elements
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* of the array pSrc[i], each with weight weight[i].
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* n <= 0 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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* GM_UNDERFLOW
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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 *WeightedMean(pDst,pSrc,weight,n)
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DEC *pDst;
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DEC **pSrc, **weight;
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int n;
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{
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int i;
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DEC dsum, *sum=&dsum, dsumw, *sumw=&dsumw;
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DEC dprod, *prod=&dprod;
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/* source must be supplied !! */
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_MacStart(GM_WMEAN);
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if (!pSrc||!weight) {
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_MacErr(GM_NULLPOINTER);
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_MacRet(GM_NULL);
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}
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if (n<=0) {
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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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_MacInVarD(weight[i]);
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}
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_MacOutVarD(pDst);
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_MacDZero(sum);
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_MacDZero(sumw);
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for (i=0;i<n;i++) {
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if (_MulDec80Bit(prod, pSrc[i], weight[i])==GM_OVERFLOW) {
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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, prod)==GM_OVERFLOW) {
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_MacErr(GM_OVERFLOW);
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_MacRet(GM_NULL);
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}
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(void) _AddDec80Bit(sumw, sumw, weight[i]);
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}
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if (_MacIsDecZ(sumw)) {
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_MacErr(GM_DIV0);
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_MacRet(GM_NULL);
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}
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pDst = DivideDecimal(pDst, sum, sumw);
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_MacRet(pDst);
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}
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