Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
branch: master
Fetching contributors…

Cannot retrieve contributors at this time

101 lines (84 sloc) 2.589 kb
<?
/* The Computer Language Benchmarks Game
http://shootout.alioth.debian.org/
contributed by anon
modified by Sergey Khripunov
*/
function energy(&$b) {
$e = 0.0;
for ($i=0,$m=sizeof($b);$i<$m;$i++) {
$b1=$b[$i];
$e += 0.5*$b1[6]*($b1[3]*$b1[3]+$b1[4]*$b1[4]+$b1[5]*$b1[5]);
for ($j=$i+1; $j<$m; $j++) {
$b2=$b[$j];
$dx=$b1[0]-$b2[0]; $dy=$b1[1]-$b2[1]; $dz=$b1[2]-$b2[2];
$e -= ($b1[6]*$b2[6])/sqrt($dx*$dx + $dy*$dy + $dz*$dz);
}
}
return $e;
}
$pi=3.141592653589793;
$solar_mass=4*$pi*$pi;
$days_per_year=365.24;
$bodies = array(array(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, $solar_mass), //Sun
array(4.84143144246472090E+00, // Jupiter
-1.16032004402742839E+00,
-1.03622044471123109E-01,
1.66007664274403694E-03 * $days_per_year,
7.69901118419740425E-03 * $days_per_year,
-6.90460016972063023E-05 * $days_per_year,
9.54791938424326609E-04 * $solar_mass),
array(8.34336671824457987E+00, // Saturn
4.12479856412430479E+00,
-4.03523417114321381E-01,
-2.76742510726862411E-03 * $days_per_year,
4.99852801234917238E-03 * $days_per_year,
2.30417297573763929E-05 * $days_per_year,
2.85885980666130812E-04 * $solar_mass),
array(1.28943695621391310E+01, // Uranus
-1.51111514016986312E+01,
-2.23307578892655734E-01,
2.96460137564761618E-03 * $days_per_year,
2.37847173959480950E-03 * $days_per_year,
-2.96589568540237556E-05 * $days_per_year,
4.36624404335156298E-05 * $solar_mass),
array(1.53796971148509165E+01, // Neptune
-2.59193146099879641E+01,
1.79258772950371181E-01,
2.68067772490389322E-03 * $days_per_year,
1.62824170038242295E-03 * $days_per_year,
-9.51592254519715870E-05 * $days_per_year,
5.15138902046611451E-05 * $solar_mass));
// offset_momentum
$px=$py=$pz=0.0;
foreach ($bodies as &$e) {
$px+=$e[3]*$e[6];
$py+=$e[4]*$e[6];
$pz+=$e[5]*$e[6];
}
$bodies[0][3]=-$px/$solar_mass;
$bodies[0][4]=-$py/$solar_mass;
$bodies[0][5]=-$pz/$solar_mass;
$pairs = array();
for ($i=0,$m=count($bodies); $i<$m; $i++)
for ($j=$i+1; $j<$m; $j++)
$pairs[] = array(&$bodies[$i], &$bodies[$j]);
$n = $argv[1];
printf("%0.9f\n", energy($bodies));
$i=0;
do {
foreach ($pairs as &$p) {
$a=&$p[0]; $b=&$p[1];
$dx=$a[0]-$b[0]; $dy=$a[1]-$b[1]; $dz=$a[2]-$b[2];
$dist = sqrt($dx*$dx + $dy*$dy + $dz*$dz);
$mag = 0.01/($dist*$dist*$dist);
$mag_a = $a[6]*$mag; $mag_b = $b[6]*$mag;
$a[3]-=$dx*$mag_b; $a[4]-=$dy*$mag_b; $a[5]-=$dz*$mag_b;
$b[3]+=$dx*$mag_a; $b[4]+=$dy*$mag_a; $b[5]+=$dz*$mag_a;
}
foreach ($bodies as &$b) {
$b[0]+=0.01*$b[3]; $b[1]+=0.01*$b[4]; $b[2]+=0.01*$b[5];
}
} while(++$i<$n);
printf("%0.9f\n", energy($bodies));
?>
Jump to Line
Something went wrong with that request. Please try again.