9 lines
230 B
Common Lisp
9 lines
230 B
Common Lisp
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(in-package :lizfcm.approx)
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(defun derivative-at (f x &optional (delta 0.01))
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(let* ((x2 (+ x delta))
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(x1 (- x delta))
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(y2 (apply f (list x2)))
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(y1 (apply f (list x1))))
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(/ (- y2 y1) (- x2 x1))))
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