[Haskell-cafe] Is the #functional programming paradigm antithetical to efficient strings? #Haskell

[Branimir Maksimovic]

Isn't that how suppose to be? 10000000 "hello worlds" ?


On 07/14/2016 06:42 AM, Geraldus wrote:
> Your rust version pushes only 10'000'000 strings from arr into str, 
> doesn't it?
>
> ср, 13 июл. 2016 г. в 16:41, Branimir Maksimovic 
> <branimir.maksimovic at gmail.com <mailto:branimir.maksimovic at gmail.com>>:
>
>     rust (no need for array but anyway)
>
>     [bmaxa at manjaro rust]$ time ./append
>     10000000 took 0.064016791
>     110000000 took 0.13466229
>
>     real    0m0.204s
>     user    0m0.167s
>     sys    0m0.033s
>
>     haskell (your fastest version)
>
>     [bmaxa at manjaro rust]$ time ./concat
>     "Done"
>
>     real    0m0.224s
>     user    0m0.220s
>     sys    0m0.000s
>
>     c++ (no array)
>
>     [bmaxa at manjaro rust]$ time ./a.out
>
>     real    0m0.115s
>     user    0m0.100s
>     sys    0m0.013s
>
>     rust:
>
>     use std::time::*;
>
>     fn main() {
>         let mut arr=Vec::new();
>         arr.reserve(10_000_000);
>         let start = Instant::now();
>         for _ in 0 .. 10_000_000 {
>             arr.push("hello world");
>         }
>         let end = start.elapsed();
>         let diff = (end.as_secs()*1000000000 + end.subsec_nanos() as
>     u64) as f64/1000000000.;
>         println!("{} took {}",arr.len(),diff);
>         let mut str = String::new();
>         str.reserve(110_000_000);
>         let start = Instant::now();
>         for i in arr {
>             str .push_str(i);
>         }
>         let end = start.elapsed();
>         let diff = (end.as_secs()*1000000000 + end.subsec_nanos() as
>     u64) as f64/1000000000.;
>         println!("{} took {}",str.len(),diff);
>     }
>
>     c++:
>
>     #include <stdio.h>
>     #include <string>
>
>
>     int main() {
>         std::string tmp;
>         tmp.reserve(110000000);
>         for (int i=0;i<10000000;i++) {
>             tmp += "hello world";
>         }
>     }
>
>     Model name:            Intel(R) Core(TM) i3-5005U CPU @ 2.00GHz
>
>
>     On 07/12/2016 05:36 AM, William Yager wrote:
>>     You picked the single slowest way to do it. Please see
>>     https://gist.github.com/wyager/df063ad4edd9a9c8b0ab762c91a79894
>>
>>     All times are on my Intel Atom Macbook. Compiled with -O3, no
>>     other options.
>>
>>     Using Lazy Bytestrings (either through the Builder interface or
>>     plain old concatenation) is about 7-7.5 times faster than string
>>     concatenation so on your computer it should take about 0.12
>>     seconds. In other words, faster than C.
>>
>>     This is my usual experience with lazy bytestrings; due to their
>>     optimization for cache size, they are extremely fast with almost
>>     no effort. They often out-perform "fast" array operations in C
>>     due to fusion and cache coherency.
>>
>>     I will note that if you want to do exactly what C does (often
>>     with only slightly different assembly output), you can often
>>     achieve this with unboxed vectors (mutable or immutable,
>>     depending on your application).
>>
>>     --Will
>>
>>     On Mon, Jul 11, 2016 at 10:24 PM, Richard A. O'Keefe
>>     <ok at cs.otago.ac.nz <mailto:ok at cs.otago.ac.nz>> wrote:
>>
>>
>>         Making a list of "Hello world" 10,000,000 times and then
>>         concatenating that list to produce a single String took
>>         0.87 seconds (start program to end program) in Haskell.
>>
>>
>>
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>
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