Path: utzoo!utgpu!water!watmath!clyde!bellcore!faline!ulysses!allegra!mit-eddie!husc6!cmcl2!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.UUCP
Newsgroups: comp.lang.c
Subject: Re: parens honored
Message-ID: <7042@brl-smoke.ARPA>
Date: 11 Jan 88 23:52:25 GMT
References: <11205@brl-adm.ARPA>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 15
Posted: Mon Jan 11 18:52:25 1988

In article <11205@brl-adm.ARPA> V4039%TEMPLEVM.BITNET@CUNYVM.CUNY.EDU (Stan Horwitz) writes:
>   EXAMPLE:  Given arrays X and Y, and XX, XY, and SSXY, the formula
>             SSXY = SUM(XY)/N - SUM(X) * SUM(Y) / N ...

I didn't understand the point of your example, but also please note
that this isn't a very robust formula.  I know better methods for
computing variance, so presumably there's also better computational
formulas for cross-correlations.

I just checked the "Numerical Recipes" book, which didn't help except
to point out that that's not the best general form for computing
linear regression coefficients.  (N should not be hardwired in.)

Perhaps you should explain what "temporary variables" the first form
involves that your rewrite eliminated.