X-Git-Url: https://git.ucc.asn.au/?p=ipdf%2Fdocuments.git;a=blobdiff_plain;f=irc%2F%23ipdf.log;h=ab047ad16de66464d2fee47fc5d406a8406f3ced;hp=89f71a4840cc7f60f482ec3d8d161e5f46e5070c;hb=a65b56f2215ca0d2d439a5de04452332f3ff4bc1;hpb=6f5f55579b969668419ea925e07f6c86442ef582

diff --git a/irc/#ipdf.log b/irc/#ipdf.log
index 89f71a4..ab047ad 100644
--- a/irc/#ipdf.log
+++ b/irc/#ipdf.log
@@ -793,3 +793,105 @@
 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
+--- Day changed Thu Apr 24 2014
+14:40 -!- You're now known as notmatches
+14:40 -!- You're now known as matches
+14:41 <@matches> Ok, less spammy channel time
+14:41 -!- mode/#ipdf [+b m:matches!*@*] by matches
+14:41 <@matches> Spam
+14:41 <@matches> Dammit
+14:42 -!- mode/#ipdf [-o matches] by matches
+14:42 < matches> Spam
+14:43 < matches> Yay
+14:43 < matches> ... this will all appear in the next git commit won't it -_-
+14:52 -!- You're now known as notmatches
+14:52 -!- You're now known as matches
+--- Day changed Sat Apr 26 2014
+00:45 -!- mode/#ipdf [+o matches] by OperServ
+00:46 <@matches> Incoming "at least it is self consistent in its wrongness" floating point conversion
+00:48 -!- mode/#ipdf [-o matches] by matches
+00:48 < matches> Still can't talk
+00:48 < matches> Excellent
+--- Day changed Sun Apr 27 2014
+17:10 < sulix> I finally got ipdf working on my laptop again by porting everything to OpenGL 3.1.
+17:10 < sulix> I'm so sorry about how ugly the code now is, by the way.
+18:04 -!- mode/#ipdf [+o matches] by OperServ
+18:04 -!- Pommers [bobgeorge33@motsugo.ucc.gu.uwa.edu.au] has joined #ipdf
+18:05 < Pommers> You know what a really good feature for a PDF reader would be? The ability to have it completely borderless without menus, so you just see the page!
+18:05 -!- Pommers [bobgeorge33@motsugo.ucc.gu.uwa.edu.au] has left #ipdf []
+18:06 <@matches> Wat
+18:06 <@matches> Well we've got that
+18:06 <@matches> We just can't read pdfs
+18:07 <@matches> Did you get much done not going to the cleanup?
+18:07 <@matches> I managed to transfer some dust from one location to another location, and then the wind blew it back in my face
+18:08 <@matches> Then I looked at Frames' proposal and despaired at how much it is actually complete and has words in it
+18:08 <@matches> I think he's onto something with his plan of actually writing things
+18:14 -!- matches changed the topic of #ipdf to: ipdf the pdf doesn't stand for pdf
+18:14 -!- matches changed the topic of #ipdf to: ipdf the pdf doesn't stand for pdf but the df stands for df
+18:14 -!- matches changed the topic of #ipdf to: Sort of
+18:15 <@matches> I need a script to auto mute me...
+18:15 < sulix> I spent basically all of today on that one commit.
+18:15 -!- mode/#ipdf [-o matches] by matches
+18:15 -!- mode/#ipdf [+o matches] by OperServ
+18:15 < sulix> Whether or not that was more useful than the cleanup remains to be seen.
+18:16 <@matches> I should look at it I guess :P
+18:16 < sulix> It compiles*
+18:16 < sulix> *but has lots of warnings.
+18:16 <@matches> It can't be worse than my tester that converts floats to floats
+18:17 < sulix> I'm pretty certain it can be and is worse.
+18:17 <@matches> However I've realised I kind of actually do need to be able to do that
+18:17 <@matches> Woah 3k+ lines
+18:17 <@matches> * 4k+ lines
+18:18 < sulix> Most of it was autogenerated, but still...
+18:18  * matches weeps for OpenGL 1
+18:18 < sulix> You don't realise how much you miss it until it's gone...
+18:19 <@matches> So what does all this stuff actually do
+18:19 <@matches> Because I could see rectangles and things just fine without it
+18:19 < sulix> Exactly the same thing as before but it works on my laptop now.
+18:19 <@matches> I see a shader program, that's obviously good
+18:20 <@matches> Actually I see code for a shader but no shader yet
+18:20 < sulix> The shaders are all #defines, I'm afraid.
+18:22 <@matches> What was wrong with your laptop?
+18:23 < sulix> It doesn't support the OpenGL compatibility mode, so --- as I was using the OpenGL 3.1 feature of "primitive restart", I had to code the entire thing in OpenGL 3.1
+18:23 < sulix> On the bright side, this paves the way for doing things like getting the GPU to use doubles.
+18:26 <@matches> Ooh
+18:27 < sulix> (also halves)
+18:27 < sulix> (halfs?)
+18:27 <@matches> Do GPUs use IEEE floats? I had a reference that seemed to be complaining they didn't
+18:27 <@matches> Although it was circa 2007
+18:28 < sulix> I don't think that there's a requirement that they internally use them, but they do read and write them.
+18:28 < sulix> A bit like how x86 processors use(d) 80 bit reals internally and rounded when reading/writing to memory.
+18:28 <@matches> Do halves have a different mantissa encoding
+18:29 <@matches> The examples given on wikipedia seem wrong
+18:30 < sulix> I think this is the canonical description: http://www.opengl.org/registry/specs/NV/half_float.txt
+18:33 <@matches> That would be before IEEE specified half (binary16) but its the same summation for the mantissa anyway
+18:33 <@matches> binary16 is (briefly) in the 2008 revised 754
+18:34 <@matches> So I think wikipedia is giving a wrong example, but I'm not confident enough to go and change wikipedia
+18:35 <@matches> Also I just realised my conversion of the mantissa to a Real is horrible
+18:35 <@matches> Oh well, it can get fixed later
+18:36 <@matches> Hopefully I can finish my fluid mechanics assignment quick enough to actually work on my progress report / proposal / thing
+18:36 <@matches> (Hah)
+18:36 -!- mode/#ipdf [-o matches] by matches
+18:37 < sulix> Yeah, I'm going to see how much Lit review I can write for tomorrow. :/