19 lines
1 KiB
Go
19 lines
1 KiB
Go
// Package numerics provides the numerical primitives used by the trajectory
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// engine: regular-grid multilinear interpolation, monotone bisection, spherical
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// kinematics, and a Runge-Kutta-4 integrator with binary-search refinement of a
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// termination point.
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//
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// Positions are carried as GeoVec (degrees and metres) and advanced with
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// GeoStep, which rotates the position along a great circle. Rates are velocities
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// (Rate: metres per second east/north/up), never degrees per second — a
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// longitude derivative carries a 1/cos(lat) factor that diverges at the poles,
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// so the singularity is absent from the formulation rather than guarded against
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// by a threshold latitude. A step that reaches a pole continues down the far
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// side on its own.
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//
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// The package has no dependencies on any domain type. Longitude wrapping into
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// [0, 360) and the sphere geometry live here; unit conversions specific to a
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// data source stay in the caller.
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//
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// All algorithms are documented in docs/numerics.tex.
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package numerics
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