• Xiaoxi (2/2) Dec 20 2014 http://www.reddit.com/r/programming/comments/2pvf68/armv7_vs_x8664_pathf...
• JN (2/4) Dec 20 2014 except for the fact that writeln didn't work :x
• David Nadlinger (5/10) Dec 20 2014 That's probably in reference to ARM. To be honest, I'm quite
• bearophile (92/94) Dec 20 2014 A little better D code:
• =?UTF-8?B?IlRow6lv?= Bueno" (6/8) Dec 20 2014 Look at the last results, C++ got updated.
• =?UTF-8?B?IlRow6lv?= Bueno" (5/14) Dec 20 2014 Ah ah, someone forgot a multiplication somewhere, I guess :)
• MattCoder (5/7) Dec 20 2014 According to the site:

"Xiaoxi" <xiaoxi 163.com> writes:

http://www.reddit.com/r/programming/comments/2pvf68/armv7_vs_x8664_pathfinding_benchmark_of_c_d_go/

didnt analyse the code, but D did quite well. :)

"JN" <666total wp.pl> writes:

On Saturday, 20 December 2014 at 10:12:40 UTC, Xiaoxi wrote:
 http://www.reddit.com/r/programming/comments/2pvf68/armv7_vs_x8664_pathfinding_benchmark_of_c_d_go/

 didnt analyse the code, but D did quite well. :)

except for the fact that writeln didn't work :x

"David Nadlinger" <code klickverbot.at> writes:

On Saturday, 20 December 2014 at 10:36:23 UTC, JN wrote:
 On Saturday, 20 December 2014 at 10:12:40 UTC, Xiaoxi wrote:
 http://www.reddit.com/r/programming/comments/2pvf68/armv7_vs_x8664_pathfinding_benchmark_of_c_d_go/

 didnt analyse the code, but D did quite well. :)

 except for the fact that writeln didn't work :x

That's probably in reference to ARM. To be honest, I'm quite
surprised that the benchmark even worked that well, given the
current state of LDC ARM support.

David

"bearophile" <bearophileHUGS lycos.com> writes:

Xiaoxi:

 http://www.reddit.com/r/programming/comments/2pvf68/armv7_vs_x8664_pathfinding_benchmark_of_c_d_go/

 didnt analyse the code, but D did quite well. :)

A little better D code:


import std.stdio, std.file, std.conv, std.string, std.datetime;

struct Route { uint dest, cost; }
alias Node = Route[];

Node[] readPlaces() {
     auto lines = "agraph".File.byLine;

     immutable numNodes = lines.front.to!uint;
     lines.popFront;
     auto nodes = new Node[numNodes];

     foreach (const line; lines) {
         immutable nums = line.split.to!(uint[]);
         if (nums.length < 3)
             break;
         nodes[nums[0]] ~= Route(nums[1], nums[2]);
     }

     return nodes;
}

uint getLongestPath(in Node[] nodes, in uint nodeID, bool[] 
visited)
pure nothrow  safe  nogc {
     visited[nodeID] = true;
     typeof(return) dMax = 0;

     foreach (immutable neighbour; nodes[nodeID])
         if (!visited[neighbour.dest]) {
             immutable dist = neighbour.cost +
                              getLongestPath(nodes, 
neighbour.dest, visited);
             if (dist > dMax)
                 dMax = dist;
         }

     visited[nodeID] = false;
     return dMax;
}

void main() {
     const nodes = readPlaces;
     auto visited = new bool[nodes.length];

     StopWatch sw;
     sw.start;
     immutable len = getLongestPath(nodes, 0, visited);
     sw.stop;
     printf("%d language D %d\n", len, sw.peek.msecs);
}




I don't remember if the D entry gets faster with ldc2 if nodes is 
immutable, this is a version that keeps it immutable as in the 
original code:


import std.stdio, std.file, std.conv, std.string, std.datetime, 
std.exception;

struct Route { uint dest, cost; }
alias Node = Route[];

Node[] readPlaces() {
     auto lines = "agraph".File.byLine;

     immutable numNodes = lines.front.to!uint;
     lines.popFront;
     auto nodes = new Node[numNodes];

     foreach (const line; lines) {
         immutable nums = line.split.to!(uint[]);
         if (nums.length < 3)
             break;
         nodes[nums[0]] ~= Route(nums[1], nums[2]);
     }

     return nodes;
}

uint getLongestPath(immutable Node[] nodes, in uint nodeID, 
bool[] visited)
pure nothrow  safe  nogc {
     visited[nodeID] = true;
     typeof(return) dMax = 0;

     foreach (immutable neighbour; nodes[nodeID])
         if (!visited[neighbour.dest]) {
             immutable dist = neighbour.cost +
                              getLongestPath(nodes, 
neighbour.dest, visited);
             if (dist > dMax)
                 dMax = dist;
         }

     visited[nodeID] = false;
     return dMax;
}

void main() {
     immutable nodes = readPlaces.assumeUnique;
     auto visited = new bool[nodes.length];

     StopWatch sw;
     sw.start;
     immutable len = getLongestPath(nodes, 0, visited);
     sw.stop;
     printf("%d language D %d\n", len, sw.peek.msecs);
}


But I think this is probably not necessary.

If you want you can submit the code to the original tester.

Bye,
bearophile

=?UTF-8?B?IlRow6lv?= Bueno" <munrek gmx.com> writes:

On Saturday, 20 December 2014 at 10:12:40 UTC, Xiaoxi wrote:
 http://www.reddit.com/r/programming/comments/2pvf68/armv7_vs_x8664_pathfinding_benchmark_of_c_d_go/

 didnt analyse the code, but D did quite well. :)

Look at the last results, C++ got updated.

x86-64
Language	Runtime (ms)
C++	1.74439
D	1828

=?UTF-8?B?IlRow6lv?= Bueno" <munrek gmx.com> writes:

On Saturday, 20 December 2014 at 14:37:40 UTC, Théo Bueno wrote:
 On Saturday, 20 December 2014 at 10:12:40 UTC, Xiaoxi wrote:
 http://www.reddit.com/r/programming/comments/2pvf68/armv7_vs_x8664_pathfinding_benchmark_of_c_d_go/

 didnt analyse the code, but D did quite well. :)

 Look at the last results, C++ got updated.

 x86-64
 Language	Runtime (ms)
 C++	1.74439
 D	1828

Ah ah, someone forgot a multiplication somewhere, I guess :)
https://github.com/logicchains/LPATHBench/commit/47d5f676f278b8d8ba7c415ff9ef6dea6666c5cf

Anyway this benchmark and these numbers are crap, using the
provided makefile I have totally different results on my laptop.

"MattCoder" <stopthespam mail.com> writes:

On Saturday, 20 December 2014 at 14:51:54 UTC, Théo Bueno wrote:
 Anyway this benchmark and these numbers are crap, using the
 provided makefile I have totally different results on my laptop.

According to the site:

"...Feel free to submit improvements to the implementations!"

:)

Matheus.