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February 10, 2014 Benchmark games, Rust, big ints and Pi | ||||
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There is some discussion in the Rust Reddit, as Rust since some time has some benchmarks on the Computer Game site: http://www.reddit.com/r/rust/comments/1xcq1q/c_gcc_vs_rust_wtf/ The source code of the Rust benchmarks is probably here: https://github.com/mozilla/rust/tree/master/src/test/bench They are mostly discussing about the very slow big int implementation. A short D implementation of the the pidigits benchmark that uses Phobos BigInts (this is not meant to compete with the entries that use GMP. A D entry using GMP is possible), adapted from the C entry by the good Ledrug: http://dpaste.dzfl.pl/821527e71343 I have not compared them, but I think it's 3-4 times slower than the best entry (that uses GMP). I suspect that if Phobos BigInts gets mutable buffers (https://d.puremagic.com/issues/show_bug.cgi?id=7013 ), this code could be modified to be rather faster. Bye, bearophile |
October 20, 2014 Re: Benchmark games, Rust, big ints and Pi | ||||
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Posted in reply to bearophile | On Monday, 10 February 2014 at 22:19:19 UTC, bearophile wrote: > http://dpaste.dzfl.pl/821527e71343 Your paste has expired / no longer there.... but the subject has come up again... http://www.wilfred.me.uk/blog/2014/10/20/the-fastest-bigint-in-the-west/ https://lobste.rs/s/sfie8j/the_fastest_bigint_in_the_west I thought to take a poke at it from this point of view. Ruby "wins" the game for shortest code... I wondered whether D could score high both on the terse/readable and speed categories. Do you still have your implementation hanging around? |
October 20, 2014 Re: Benchmark games, Rust, big ints and Pi | ||||
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Posted in reply to John Carter | John Carter:
> Your paste has expired / no longer there.... but the subject has come up again...
> ...
> Do you still have your implementation hanging around?
I think it was this. *Untested*:
void main(string[] args) {
import core.stdc.stdio, std.bigint, core.stdc.stdlib;
immutable n = (args.length == 2) ? args[1].ptr.atoi : 100;
BigInt acc, den = 1, num = 1;
for (uint i, k; i < n; ) {
immutable k2 = ++k * 2U + 1U;
acc = (acc + num * 2U) * k2;
den *= k2;
num *= k;
if (num > acc)
continue;
immutable d = ((num * 3 + acc) / den) % 10U;
if (d != ((num * 4 + acc) / den) % 10U)
continue;
putchar('0' + d);
if (++i % 10 == 0)
printf("\t:%u\n", i);
acc = (acc - den * d) * 10U;
num *= 10U;
}
}
Bye,
bearophile
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