60 lines
1.3 KiB
AppleScript
60 lines
1.3 KiB
AppleScript
-- ARITHMETIC GEOMETRIC MEAN -------------------------------------------------
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property tolerance : 1.0E-5
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-- agm :: Num a => a -> a -> a
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on agm(a, g)
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script withinTolerance
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on |λ|(m)
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tell m to ((its an) - (its gn)) < tolerance
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end |λ|
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end script
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script nextRefinement
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on |λ|(m)
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tell m
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set {an, gn} to {its an, its gn}
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{an:(an + gn) / 2, gn:(an * gn) ^ 0.5}
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end tell
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end |λ|
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end script
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an of |until|(withinTolerance, ¬
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nextRefinement, {an:(a + g) / 2, gn:(a * g) ^ 0.5})
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end agm
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-- TEST ----------------------------------------------------------------------
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on run
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agm(1, 1 / (2 ^ 0.5))
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--> 0.847213084835
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end run
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-- GENERIC FUNCTIONS ---------------------------------------------------------
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-- until :: (a -> Bool) -> (a -> a) -> a -> a
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on |until|(p, f, x)
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set mp to mReturn(p)
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set v to x
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tell mReturn(f)
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repeat until mp's |λ|(v)
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set v to |λ|(v)
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end repeat
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end tell
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return v
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end |until|
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-- Lift 2nd class handler function into 1st class script wrapper
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-- mReturn :: Handler -> Script
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on mReturn(f)
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if class of f is script then
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f
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else
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script
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property |λ| : f
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end script
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end if
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end mReturn
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