From: C R Onjob Date: Wed, 23 Apr 2014 17:00:02 +0000 (+0800) Subject: Automatic commit of irc logs X-Git-Url: https://git.ucc.asn.au/?p=ipdf%2Fdocuments.git;a=commitdiff_plain;h=eeeaaae3227fd4427a78f4ab75e8a4f414b3626d Automatic commit of irc logs If you tell the truth you don't have to remember anything. -- Mark Twain --- diff --git a/irc/#ipdf.log b/irc/#ipdf.log index 89f71a4..f1a939e 100644 --- a/irc/#ipdf.log +++ b/irc/#ipdf.log @@ -793,3 +793,25 @@ 17:35 <@matches> The CQM lecturer for physics found a bug in Mathematica's number representation once that she showed us 17:35 <@matches> Apparently she reported it years ago and it's still there 17:36 <@matches> This segued nicely into why we should learn fortran +--- Day changed Wed Apr 23 2014 +14:00 <@matches> IEEE's float encoding is inconvenient +14:01 <@matches> The mantissa is like, reversed +14:01 <@matches> b_{23-i} * 2^{-i} +14:19 <@matches> And the implicit extra 1 except when it isn't is a pain in the ass as well +14:19 <@matches> It's like +14:19 <@matches> I can't just copy the right bits I have to think +14:19 <@matches> What is this +14:19 <@matches> Mental effort +14:19 <@matches> Blargh +14:20 <@matches> I should have just stuck with the 8 bit floats with their 2 sign bits +14:20 <@matches> The hydra float +15:17 <@matches> Wow you get really different representations with an IEEE encoding of the bits +15:17 <@matches> ... +15:17 <@matches> I think I liked just treating the two parts as integers in the order they were stored better +15:18 <@matches> I have to call pow(3) and a floating point division for every '1' in the mantissa to get it to agree with IEEE +15:19 <@matches> Unless I'm missing some obvious trick +15:20 <@matches> But in IEEE the mantissa is not an integer +15:37 <@matches> Ooookkk +15:38 <@matches> You're precision doesn't disappear as fast when you do it that way +15:38 <@matches> Your +15:38 <@matches> Whatever