Orbital elements: Difference between revisions

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 TODO: pick an example from a reputable source, and bring the algorithm description onto this site. (Restating those pages in concise a fashion comprehensible to the coders and readers of this site will be a good exercise.)
 <br><br>
+=={{header|11l}}==
+{{trans|Python}}
+<lang 11l>F mulAdd(v1, x1, v2, x2)
+   R v1 * x1 + v2 * x2
+F rotate(i, j, alpha)
+   R [mulAdd(i, cos(alpha), j, sin(alpha)), mulAdd(i, -sin(alpha), j, cos(alpha))]
+F orbitalStateVectors(semimajorAxis, eccentricity, inclination, longitudeOfAscendingNode, argumentOfPeriapsis, trueAnomaly)
+   V i = (1.0, 0.0, 0.0)
+   V j = (0.0, 1.0, 0.0)
+   V k = (0.0, 0.0, 1.0)
+   V p = rotate(i, j, longitudeOfAscendingNode)
+   i = p[0]
+   j = p[1]
+   p = rotate(j, k, inclination)
+   j = p[0]
+   p = rotate(i, j, argumentOfPeriapsis)
+   i = p[0]
+   j = p[1]
+   V l = I (eccentricity == 1.0) {2.0} E 1.0 - eccentricity * eccentricity
+   l *= semimajorAxis
+   V c = cos(trueAnomaly)
+   V s = sin(trueAnomaly)
+   V r = 1 / (1.0 + eccentricity * c)
+   V rprime = s * r * r / l
+   V position = mulAdd(i, c, j, s) * r
+   V speed = mulAdd(i, rprime * c - r * s, j, rprime * s + r * c)
+   speed = normalize(speed) * sqrt(2.0 / r - 1.0 / semimajorAxis)
+   R [position, speed]
+V ps = orbitalStateVectors(1.0, 0.1, 0.0, 355.0 / (113.0 * 6.0), 0.0, 0.0)
+print(‘Position : ’ps[0])
+print(‘Speed    : ’ps[1])</lang>
+{{out}}
+<pre>
+Position : (0.787295801, 0.45454549, 0)
+Speed    : (-0.5477226, 0.948683274, 0)
+</pre>
 =={{header|ALGOL W}}==