Path: utzoo!utgpu!watmath!clyde!att!rutgers!mailrus!ames!amdahl!nsc!taux01!taux02!amos From: amos@taux02.UUCP (Amos Shapir) Newsgroups: comp.arch Subject: Re: Professional Programmers (was: Seeing the future) Message-ID: <331@taux02.UUCP> Date: 3 Dec 88 11:40:56 GMT References: <1984@eos.UUCP> <28200245@mcdurb> <321@taux02.UUCP> <32353@think.UUCP> Organization: National Semiconductor (IC) Ltd, Israel Home of the 32532 Lines: 21 Hdate: 24 Kislev 5749 In article <32353@think.UUCP> you write: >In article <321@taux02.UUCP> amos@taux02.UUCP (Amos Shapir) writes: >>Most of what a professional programmer does when helping scientists, >>is to change things like cos(atan(x))**2 to 1/(1+x*x) . > >What does this have to do with being a professional PROGRAMMER? The >above identity is a MATHEMATICAL fact, having nothing to do with >computers, except insofar as the above statements in a program >approximate the corresponding mathematical operations. This is exactly the point I was trying to make - to a mathematician, these two expressions are identical and interchangeable; to a programmer, one is an expression requiring two function calls (twice if your compiler is lousy) involving hundreds of operations, while the other requires just one multiply and one divide. It's the programmer's job to know these facts and use them. -- Amos Shapir amos@nsc.com National Semiconductor (Israel) P.O.B. 3007, Herzlia 46104, Israel Tel. +972 52 522261 TWX: 33691, fax: +972-52-558322 34 48 E / 32 10 N (My other cpu is a NS32532)