Orbital elements: Difference between revisions
Perl 5 translation
m (→{{header|Perl 6}}: link to the Clifford library) |
(Perl 5 translation) |
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Line 4:
TODO: pick an example from a reputable source.
=={{header|Perl}}==
{{trans|Perl 6}}
<lang perl>use strict;
use warnings;
use Math::Vector::Real;
sub orbital_state_vectors {
my (
$semimajor_axis,
$eccentricity,
$inclination,
$longitude_of_ascending_node,
$argument_of_periapsis,
$true_anomaly
) = @_[0..5];
my ($i, $j, $k) = (V(1,0,0), V(0,1,0), V(0,0,1));
sub rotate {
my $alpha = shift;
@_[0,1] = (
+cos($alpha)*$_[0] + sin($alpha)*$_[1],
-sin($alpha)*$_[0] + cos($alpha)*$_[1]
);
}
rotate $longitude_of_ascending_node, $i, $j;
rotate $inclination, $j, $k;
rotate $argument_of_periapsis, $i, $j;
my $l = $eccentricity == 1 ? # PARABOLIC CASE
2*$semimajor_axis :
$semimajor_axis*(1 - $eccentricity**2);
my ($c, $s) = (cos($true_anomaly), sin($true_anomaly));
my $r = $l/(1 + $eccentricity*$c);
my $rprime = $s*$r**2/$l;
my $position = $r*($c*$i + $s*$j);
my $speed =
($rprime*$c - $r*$s)*$i + ($rprime*$s + $r*$c)*$j;
$speed /= abs($speed);
$speed *= sqrt(2/$r - 1/$semimajor_axis);
{
position => $position,
speed => $speed
}
}
use Data::Dumper;
print Dumper orbital_state_vectors
1, # semimajor axis
0.1, # eccentricity
0, # inclination
355/113/6, # longitude of ascending node
0, # argument of periapsis
0 # true-anomaly
;
</lang>
{{out}}
<pre>$VAR1 = {
'position' => bless( [
'0.77942284339868',
'0.450000034653684',
'0'
], 'Math::Vector::Real' ),
'speed' => bless( [
'-0.552770840960444',
'0.957427083179762',
'0'
], 'Math::Vector::Real' )
};</pre>
=={{header|Perl 6}}==
Line 29 ⟶ 106:
my \l = $eccentricity == 1 ?? # PARABOLIC CASE
2*$semimajor-axis !!
$semimajor-axis*(1 - $eccentricity**2);
my ($c, $s) = map {.($true-anomaly)}, &cos, &sin;
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