gambas-source-code/benchmark/nbody.pl
Benoît Minisini 52b25350e1 [BENCHMARKS]
* NEW: New N-Poly benchmarks.
* NEW: All benchmarks times were updated on the wiki.


git-svn-id: svn://localhost/gambas/trunk@4582 867c0c6c-44f3-4631-809d-bfa615b0a4ec
2012-03-30 22:27:20 +00:00

112 lines
3.2 KiB
Perl
Executable file

#!/usr/bin/perl -w
# The Computer Language Shootout
# http://shootout.alioth.debian.org/
#
# contributed by Christoph Bauer
# converted into Perl by Márton Papp
# fixed and cleaned up by Danny Sauer
# optimized by Jesse Millikan
use constant PI => 3.141592653589793;
use constant SOLAR_MASS => (4 * PI * PI);
use constant DAYS_PER_YEAR => 365.24;
# Globals for arrays... Oh well.
# Almost every iteration is a range, so I keep the last index rather than a count.
my (@xs, @ys, @zs, @vxs, @vys, @vzs, @mass, $last);
sub advance($)
{
my ($dt) = @_;
my ($mm, $mm2, $j, $dx, $dy, $dz, $distance, $mag);
# This is faster in the outer loop...
for (0..$last) {
# But not in the inner loop. Strange.
for ($j = $_ + 1; $j < $last + 1; $j++) {
$dx = $xs[$_] - $xs[$j];
$dy = $ys[$_] - $ys[$j];
$dz = $zs[$_] - $zs[$j];
$distance = sqrt($dx * $dx + $dy * $dy + $dz * $dz);
$mag = $dt / ($distance * $distance * $distance);
$mm = $mass[$_] * $mag;
$mm2 = $mass[$j] * $mag;
$vxs[$_] -= $dx * $mm2;
$vxs[$j] += $dx * $mm;
$vys[$_] -= $dy * $mm2;
$vys[$j] += $dy * $mm;
$vzs[$_] -= $dz * $mm2;
$vzs[$j] += $dz * $mm;
}
# We're done with planet $_ at this point
# This could be done in a seperate loop, but it's slower
$xs[$_] += $dt * $vxs[$_];
$ys[$_] += $dt * $vys[$_];
$zs[$_] += $dt * $vzs[$_];
}
}
sub energy
{
my ($e, $i, $dx, $dy, $dz, $distance);
$e = 0.0;
for $i (0..$last) {
$e += 0.5 * $mass[$i] *
($vxs[$i] * $vxs[$i] + $vys[$i] * $vys[$i] + $vzs[$i] * $vzs[$i]);
for ($i + 1..$last) {
$dx = $xs[$i] - $xs[$_];
$dy = $ys[$i] - $ys[$_];
$dz = $zs[$i] - $zs[$_];
$distance = sqrt($dx * $dx + $dy * $dy + $dz * $dz);
$e -= ($mass[$i] * $mass[$_]) / $distance;
}
}
return $e;
}
sub offset_momentum
{
my ($px, $py, $pz) = (0.0, 0.0, 0.0);
for (0..$last) {
$px += $vxs[$_] * $mass[$_];
$py += $vys[$_] * $mass[$_];
$pz += $vzs[$_] * $mass[$_];
}
$vxs[0] = - $px / SOLAR_MASS;
$vys[0] = - $py / SOLAR_MASS;
$vzs[0] = - $pz / SOLAR_MASS;
}
# @ns = ( sun, jupiter, saturn, uranus, neptune )
@xs = (0, 4.84143144246472090e+00, 8.34336671824457987e+00, 1.28943695621391310e+01, 1.53796971148509165e+01);
@ys = (0, -1.16032004402742839e+00, 4.12479856412430479e+00, -1.51111514016986312e+01, -2.59193146099879641e+01);
@zs = (0, -1.03622044471123109e-01, -4.03523417114321381e-01, -2.23307578892655734e-01, 1.79258772950371181e-01);
@vxs = map {$_ * DAYS_PER_YEAR}
(0, 1.66007664274403694e-03, -2.76742510726862411e-03, 2.96460137564761618e-03, 2.68067772490389322e-03);
@vys = map {$_ * DAYS_PER_YEAR}
(0, 7.69901118419740425e-03, 4.99852801234917238e-03, 2.37847173959480950e-03, 1.62824170038242295e-03);
@vzs = map {$_ * DAYS_PER_YEAR}
(0, -6.90460016972063023e-05, 2.30417297573763929e-05, -2.96589568540237556e-05, -9.51592254519715870e-05);
@mass = map {$_ * SOLAR_MASS}
(1, 9.54791938424326609e-04, 2.85885980666130812e-04, 4.36624404335156298e-05, 5.15138902046611451e-05);
$last = @xs - 1;
offset_momentum();
for (1..10)
{
printf ("%.9f\n", energy());
# This does not, in fact, consume N*4 bytes of memory
for (1..100000){
advance(0.01);
}
}
printf ("%.9f\n", energy());