user2994cb

11 ms·

61.
by user2994cb 9y ago
Code to print both the Stern-Brocot tree and the Calkin-Wilf tree, using the algorithm in that paper: def fractions(): a,b,c,d = 1,0,0,1 while True: yield a,b,c,d if a == 1 and b == 0 and d == 1: a,
62.
by user2994cb 9y ago
The audiobook by Jim Norton (aka Bishop Brennan) is a good way in to FW: https://www.youtube.com/watch?v=JAc901X7gK0
63.
by user2994cb 9y ago
Another visualization, using JS to solve the Langrangian: https://matthewarcus.github.io/lagrange/
64.
by user2994cb 9y ago
Actually, having Some(x) be just a pointer to x seems to work fine without an explicit tag, as dragonwriter says below.
65.
by user2994cb 9y ago
Dunno, but I'd have thought that you can make None look like a null pointer, but Some(p) needs to be tagged in some way.
66.
by user2994cb 9y ago
Aren't null pointers just a variation on the Maybe Monad?
67.
Clebsch Cubic Surface on Shadertoy(shadertoy.com)
1 points by user2994cb 9y ago|0 comments
68.
by user2994cb 9y ago
2014 interview with Delany about this here: http://shetterly.blogspot.co.uk/2014/07/a-conversation-with-...
69.
by user2994cb 9y ago
Generating necklaces and bracelets is fun too, see eg. http://www.sciencedirect.com/science/article/pii/S0304397512...
70.
by user2994cb 10y ago
Looking at it a bit more - the double recursion in the radiance function for refraction would make things a bit awkward in WebGL.
71.
by user2994cb 10y ago
Looks like it would make a nice glsl/WebGL fragment shader (might be even shorter as the vector operations are predefined). Can't see one listed on the page, but then it's mostly from a few years back.
72.
by user2994cb 10y ago
Seems to need -mavx2 to really go to town with 64 bit: https://godbolt.org/g/6EFYeY
73.
by user2994cb 10y ago
Harder to vectorize 64-bit arithmetic?
74.
by user2994cb 10y ago
That's nice. Here's a (recursive) Python implementation: http://ideone.com/z1sUp4
75.
by user2994cb 10y ago
And Dan Boneh's Coursera course is excellent too (maybe one day he will get around to doing the endlessly postponed part 2).
76.
by user2994cb 10y ago
Also, section 9.6.5 advocates MAC-then-encrypt over encrypt-then-MAC - presumably the flaws in this approach have only become apparent since the book was published. An interesting historical document though.
77.
by user2994cb 10y ago
As noted elsewhere, bipyramids and trapezohedra can have unlimited (even) numbers of sides - not very practical though.
78.
by user2994cb 10y ago
You can also use the duals of (convex) uniform polyhedra (as here) - uniform polyhedra have equivalent vertices, their duals have equivalent faces.
79.
by user2994cb 10y ago
If you are going to go 4 dimensional, you'll be wanting the dual of an omnitruncated 120-cell, giving a d14400: https://en.wikipedia.org/wiki/Runcinated_120-cells
80.
by user2994cb 10y ago
Most fast methods for computing fib(n) come down to some variation of repeated squaring, so the time is dominated by the last multiplication (since the number of digits is doubling each time).
81.
by user2994cb 10y ago
Nice. A cut down version using base-10: X = 10**3 print X**16//(X*X-X-1) # 1001002003005008013021034055089144233377610 It's like a sideways addition version of the standard Haskell lazy list version: fib = 0 :
82.
by user2994cb 10y ago
That should be "q s [] = [s]", otherwise you get 92 copies of the empty list.
83.
by user2994cb 10y ago
Actually, this is better (and no less clear): import Data.List queens n = q [] [0..n-1] where q s [] = [[]] q s as = concatMap (\a -> q (a:s) (delete a as)) (filter (f 1 s) as) f _ [] a = True f n (b:s) a = a /= b+
84.
by user2994cb 10y ago
Well, here's a fairly compact Haskell function that should be reasonably efficient (no fancy stuff mind): queens n = q n n [[]] where q 0 m ss = ss q n m ss = q (n-1) m (concatMap (\s->(map (:s)(filter (f 1 s) [0..m-1])))
85.
by user2994cb 10y ago
Nice, I haven't seen that one (I was at Churchill, which doesn't have a decent sundial AFAIK, despite Frank King being a Fellow ("Chairman of the British Sundial Society" apparently - he did the Queens' recalibratio
86.
by user2994cb 10y ago
Or consider the Queens' College sundial: http://www.queens.cam.ac.uk/life-at-queens/about-the-college...
87.
Dodecahedral tesselation of the hypersphere [video](youtube.com)
2 points by user2994cb 11y ago|0 comments
88.
by user2994cb 11y ago
In this case, it seems the ioctl call will do the null termination & in fact, the kernel itself uses strcpy for that field (presumably OK since the device structure has a null terminated name): https://git.kernel.org/cgi
89.
by user2994cb 11y ago
http://matthewarcus.github.io/polyjs/clebsch.html
90.
Clebsch Surface as THREE.js particle system(matthewarcus.github.io)
2 points by user2994cb 11y ago|0 comments

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