Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!burl!hou3c!hocda!houxm!houxz!vax135!floyd!whuxle!mit-eddie!genrad!decvax!cca!ima!haddock!johnl From: johnl@haddock.UUCP Newsgroups: net.lang Subject: Re: Implementation of scientific functio - (nf) Message-ID: <184@haddock.UUCP> Date: Tue, 12-Jun-84 23:37:15 EDT Article-I.D.: haddock.184 Posted: Tue Jun 12 23:37:15 1984 Date-Received: Thu, 14-Jun-84 00:25:12 EDT Lines: 16 #R:sdccsu3:-190500:haddock:12300003:000:641 haddock!johnl Jun 9 19:41:00 1984 People have been studying numerical algorithms for a long time, and there are many references that you could look up. For most transcendental functions, the usual approach is to precondition the arguments and check for special cases, and then compute a polynomial which approximates the desired function. Look at the sources for the C math library where there are comments referring you back to their origins both to see some algorithms and get the name of the source book they used. In the particular case of square root, Newton's method provides an interative method which converges in log2(wordsize), i.e. fast. John Levine, ima!johnl