Article View: comp.lang.pascal.misc
Article #10Re: Tough FACTORIAL math problem...
From: Alasdair McIntyre
Date: Fri, 23 Feb 1996 16:04
Date: Fri, 23 Feb 1996 16:04
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1534 bytes
Risto Lankinen <risto.lankinen@ntc.nokia.com> wrote: > >There is an algorithm that calculates the last non-zero _binary_ >digit of ANY factorial - with SUB-LOGARITHMIC time even in the worst >case!!! > >Mail me if interested but be prepared to explain what you need it >for. The algorithm is indeed very VERY fast, and so I don't want to >give it away without being credited at least. Also, please mention >"rightmost non-zero binary digit algorithm" in your request. > A more interesting problem would be to generalise this and seek the rightmost non-zero digit of n! in base b for arbitrary n and b>2 ;-). Thoughts anyone? I guess for a really general problem we should allow n real - last digit of Gamma(0.5)... -- Alasdair McIntyre alasdair@thermoteknix.co.uk
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Path: arc1-ca.pugleaf.net!mail2news.demon.co.uk!thermo.demon.co.uk From: Alasdair McIntyre <alasdair@thermoteknix.co.uk> Newsgroups: comp.lang.pascal.misc,comp.lang.c++,comp.lang.c,comp.lang.pascal.borland Subject: Re: Tough FACTORIAL math problem... Date: Fri, 23 Feb 1996 16:04:35 GMT Organization: Thermoteknix Systems Limited Message-ID: <188178796wnr@thermoteknix.co.uk> References: <4fr8be$ass@news.iconn.net> <4g0giv$94s@sun132.spd.dsccc.com> <4gbsir$opr@axl02it.ntc.nokia.com> <4gintg$1f7@antares.dfma.com> Reply-To: alasdair@thermoteknix.co.uk X-NNTP-Posting-Host: thermo.demon.co.uk X-Broken-Date: Fri, 23 Feb 1996 12:45:49 0100 X-Newsreader: Newswin Alpha 0.9 X-Mail2News-Path: disperse.demon.co.uk!post.demon.co.uk!thermo.demon.co.uk