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

[Geraldus]

Oh, sorry, yes it.

чт, 14 июл. 2016 г. в 9:56, Branimir Maksimovic <
branimir.maksimovic at gmail.com>:

> 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>:
>
>> 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>
>> 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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