Path: csiph.com!eternal-september.org!feeder.eternal-september.org!nntp.eternal-september.org!.POSTED!not-for-mail From: Tim Rentsch Newsgroups: comp.arch Subject: Re: IA-64 Date: Thu, 12 Mar 2026 21:07:34 -0700 Organization: A noiseless patient Spider Lines: 26 Message-ID: <86pl5874op.fsf@linuxsc.com> References: <10n6ts2$3fjht$1@dont-email.me> <10o9s6b$34qug$1@dont-email.me> <20260304202556.000063d9@yahoo.com> <10oa6tk$38csm$1@dont-email.me> <10onere$3o39t$1@dont-email.me> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Date: Fri, 13 Mar 2026 04:07:38 +0000 (UTC) Injection-Info: dont-email.me; posting-host="cb1c5db134e2203ca5fd5b23b9ffc3a7"; logging-data="2855307"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19kzcXTmWrm6RfMveFL6mVXPDDjLMSTOL8=" User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.4 (gnu/linux) Cancel-Lock: sha1:SZwfl+ozaLasOLS1koW5hWht3fQ= sha1:IN/gFf2Hu+uszVCN4/DfgZ3oVtc= Xref: csiph.com comp.arch:115309 Terje Mathisen writes: > Kent Dickey wrote: > >> There is one very reasonable use case: testing a random number generator. >> A useful test is to ensure numbers are uncorrelated, so you get 3 random >> numbers called A, B, C, and you look up A*N*N + B*N + C to count the number >> of times you see A followed by B followed by C, where N is the range of >> the random value, say, 0 - 1023. This would be an array of 1 billion 32-bit > > I would be quite happy with half the size, i.e. 1e9 u16 entries. > >> values. You get 1000 billion random numbers, and then look through to make >> sure most buckets have a value around 1000. Any buckets less than 500 or >> more than 1500 might be considered a random number generator failure. >> This is a useful test since it intuitively makes sense--if some patterns are >> too likely (or unlikely), then you know you have a problem with your >> "random" numbers. > > I haven't done the math, but I would guess getting any deviation > outside the 800-1200 range would be quite unlikely, and at least > suspicious! I think your intuition may be somewhat askew here. I also haven't done any math, but looking at some empirical results suggests the range of 800-1200 is near the boundary of "unsurprising values".