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