11 lines
437 B
Racket
11 lines
437 B
Racket
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(define ((adaptive method ε) F h0)
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(case-lambda
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[(x y) (((adaptive method ε) F h0) x y h0)]
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[(x y h)
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(match-let* ([(list x0 y0) ((method F h) x y)]
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[(list x1 y1) ((method F (/ h 2)) x y)]
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[(list x1 y1) ((method F (/ h 2)) x1 y1)]
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[τ (abs (- y1 y0))]
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[h′ (if (< τ ε) (min h h0) (* 0.9 h (/ ε τ)))])
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(list x1 (+ y1 τ) (* 2 h′)))]))
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