Automatic commit of irc logs

Are you sure the back door is locked?

diff --git a/irc/#ipdf.log b/irc/#ipdf.log
index 8b00f10..3729fc3 100644 (file)
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@@ -1992,3 +1992,55 @@
 23:43 <@sulix> The code is a little bit ugly, and for that I am sorry, but blame the fact that the GL feature that makes this nice is only about a year old and so nothing supports it.
 23:43 <@sulix> So we're basically uploading all of the raw document data into a huge texture.
 23:47 <@sulix> (If you ask me, the GPU ones also look slightly nicer, though that's probably a bug)
+--- Day changed Thu Jun 19 2014
+13:55 <@matches> From those papers I was under the impression just rendering a bezier on a GPU was an impressive feat, so well done :P
+13:57 <@sulix> (It's basically just a direct port of your CPU implementation, tbh)
+13:59 <@matches> When I zoom out the GPU ones look nicer, there's probably something wrong with my Bresenham implementation
+13:59 <@matches> Although it was mostly shamelessly copied from "Computer Graphics"
+13:59 <@matches> Except they were like "Here it is for 0 < m < 1, the rest can be done by symmetry"
+14:02 <@matches> The lines definitely have gaps on the CPU, and they also seem too thick as you zoom out
+14:02 <@matches> Having said that, I don't think the GPU starts at x0,y0
+14:03 <@matches> Anyway I'm going to implement a Rational number type and see if anything exciting happens (that's how you do research right?)
+14:06 <@matches> Fortunately I sort of did most of this for one of the codejam problems (where it turned out I didn't really need Rational numbers but I thought I did)
+14:20 <@sulix> Fixed the missing bit off the end.
+16:43 <@matches> I suspect Rationals are either not a very good idea, or there is a bug in one of my fundamental operations
+16:43 <@matches> +, -, *, / are hard
+16:56 <@sulix> Is it at least a pretty bug?
+16:59 <@matches> Um...
+16:59 <@matches> No
+17:00 <@matches> It seems buggy for anything other than the {0,0,1,1} starting view
+17:14 <@matches> I suspect it's the expf in the mouse wheel scrolling
+17:14 <@matches> Since you know, exp is definitely not a rational number...
+17:15 <@matches> Hmm, but it shouldn't matter because it will just convert to the nearest rational number
+17:16 <@matches> ie: p = (int64_t)(whatever*1e10) q = (int64_t)1e10
+17:28 <@matches> Oh
+17:28 <@matches> Oh
+17:28 <@matches> Head -> Desk
+17:28 <@matches> Rational & operator*=(const Rational & r) {this->operator=(*this*r); return *this;}
+17:28 <@matches> Rational & operator/=(const Rational & r) {this->operator=(*this*r); return *this;}
+17:29 <@matches> Rational & operator-=(const Rational & r) {this->operator=(*this+r); return *this;}
+17:29 <@matches> I think the worst part is that I actually said "It is probably a bug in my +,-,*,/
+17:29 <@matches> And it still took me this long to notice
+17:30 <@matches> The second worst thing is I've made that sort of mistake like 1000 times before
+17:30 <@matches> The third worst thing is I am recalling that article where the guy says "At least plus and times are sort of the same thing"
+17:30 <@sulix> Feel the power of copy and paste flowing through you.
+17:32 <@matches> Well let's not celebrate just yet, the view still goes to shit. Just slightly slower :P
+17:33 -!- matches changed the topic of #ipdf to: NaNpdf
+17:33 <@matches> Our document supports a view of {-inf,-inf,nan,nan} thus making it truly infinite precision
+17:34 <@sulix> I had that happen a lot when I was writing the original zoom code.
+18:19 <@matches> So I suspect that Rationals are just a really shitty number representation :P
+18:20 <@matches> Specifically, you get integer overflows really really fast
+18:20 <@matches> And if you are going to have a Rational that's BigInt / BigInt you may as well just have a BigFloat
+18:21 <@matches> The ancients were probably right.
+18:21 <@matches> When they decided not to use rationals.
+18:23 <@matches> I guess floats are rationals technically, I mean the representation using P/Q
+18:23 <@matches> I kind of wish I'd done some pure maths here...
+18:23 <@matches> Or paid more attention in second year
+18:28 <@matches> At least I sort of have conclusive evidence that rationals suck. As opposed to "it should be obvious to anyone with half a brain"
+19:00 <@sulix> Floats are not rationals.
+19:00 <@sulix> Not exactly.
+19:01 <@sulix> Something which can be stored in a finite amount of space as a rational cannot always be stored in a finite amount of space as a float, but not vice-versa.
+19:01 <@sulix> e.g.: 1/3
+19:04 <@sulix> Basically floats = rationals where the denominator must be a power of two.
+19:05 <@sulix> (Of course, these are all the same in the limit, but the limit of a cauchy sequence of rationals gives the reals, so the point is kinda moot, there, anyway)
+19:18 <@matches> Yeah floats are a subset of the rationals I think I meant