Orbital elements: Difference between revisions
Added Lua
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<pre>Position : (0.7794228433986797, 0.45000003465368416, 0.0)
Speed : (-0.5527708409604438, 0.9574270831797618, 0.0)</pre>
=={{header|Lua}}==
{{Trans|C}}...which is translation of Kotlin which is ...
<syntaxhighlight lang="lua">
do -- orbital elements
local function Vector( x, y, z )
return { x = x, y= y, z = z }
end
local function add( v, w )
return Vector( v.x + w.x, v.y + w.y, v.z + w.z )
end
local function mul( v, m )
return Vector( v.x * m, v.y * m, v.z * m )
end
local function div( v, d )
return mul( v, 1.0 / d )
end
local function vabs( v )
return math.sqrt( v.x * v.x + v.y * v.y + v.z * v.z )
end
local function mulAdd( v1, v2, x1, x2 )
return add( mul( v1, x1 ), mul( v2, x2 ) )
end
local function vecAsStr( v )
return string.format( "(%.17g", v.x )..string.format( ", %.17g", v.y )..string.format( ", %.17g)", v.z )
end
local function rotate( i, j, alpha )
return mulAdd( i, j, math.cos( alpha ), math.sin( alpha ) )
, mulAdd( i, j, -math.sin( alpha ), math.cos( alpha ) )
end
local function orbitalStateVectors( semimajorAxis, eccentricity, inclination
, longitudeOfAscendingNode, argumentOfPeriapsis
, trueAnomaly
)
local i, j, k = Vector( 1.0, 0.0, 0.0 ), Vector( 0.0, 1.0, 0.0 ), Vector( 0.0, 0.0, 1.0 )
local L = 2.0
i, j = rotate( i, j, longitudeOfAscendingNode )
j, _ = rotate( j, k, inclination )
i, j = rotate( i, j, argumentOfPeriapsis )
if eccentricity ~= 1.0 then L = 1.0 - eccentricity * eccentricity end
L = L * semimajorAxis
local c, s = math.cos( trueAnomaly ), math.sin( trueAnomaly )
local r = L / ( 1.0 + eccentricity * c )
local rprime = s * r * r / L;
local position = mul( mulAdd( i, j, c, s ), r )
local speed = mulAdd( i, j, rprime * c - r * s, rprime * s + r * c )
speed = div( speed, vabs( speed ) )
speed = mul( speed, math.sqrt( 2.0 / r - 1.0 / semimajorAxis ) )
return position, speed
end
local longitude = 355.0 / ( 113.0 * 6.0 )
local position, speed = orbitalStateVectors( 1.0, 0.1, 0.0, longitude, 0.0, 0.0 )
print( "Position : "..vecAsStr( position ) )
print( "Speed : "..vecAsStr( speed ) )
end</syntaxhighlight>
{{out}}
<pre>
Position : (0.77942284339867973, 0.45000003465368416, 0)
Speed : (-0.55277084096044382, 0.95742708317976177, 0)
</pre>
=={{header|Nim}}==
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