Modern C++ Lamentations

[Steven Schveighoffer]

On 12/31/18 8:20 AM, Atila Neves wrote:
> On Sunday, 30 December 2018 at 22:31:27 UTC, Walter Bright wrote:
>> On 12/30/2018 5:18 AM, Atila Neves wrote:
>>> On Saturday, 29 December 2018 at 09:29:30 UTC, Walter Bright wrote:
>>>> http://aras-p.info/blog/2018/12/28/Modern-C-Lamentations/
>>>>
>>>> Time to show off your leet D skilz and see how good we can do it in D!
>>>
>>> I'm on it. As I write, I'm timing (compile and run time) several C++, 
>>> D, and Rust implementations and writing a blog post. I'm only on the 
>>> 2nd implementation but D is winning... :)
>>>
>>> I'm going to shamelessly steal Timon's range code in this thread and 
>>> the generator one posted on reddit.
>>
>> Wow! I'm looking forward to it.
> 
> Blog:
> 
> https://atilanevesoncode.wordpress.com/2018/12/31/comparing-pythagorean-triples-in-c-d-and-rust/ 
> 
> 
> Reddit:
> 
> https://www.reddit.com/r/programming/comments/ab71ag/comparing_pythagorean_triples_in_c_d_and_rust/ 
> 
> 
> 
> Hacker news something something dark side.
> 
> 

I tried the version I came up with with a dedicated looping range 
(https://run.dlang.io/is/hkqhvZ), cuts the range version down to 550ms 
(my timings are on my macbook, but my baseline was literally exactly 
what yours was, 154ms).

In any case, it does seem like the optimizer/compiler is much better at 
dealing with nested loops than 3 ranges. This is probably a case where 
the low level code is so fast (doing 3 multiplications, an addition and 
an equality check) that the loop processing becomes significant.

-Steve