Euler method: Difference between revisions

<lang lisp>;; slightly more idiomatic Common Lisp version

(defun newton-cooling (time temperature)

"Newton's cooling law, f(t,T) = -0.07*(T-20)"

(declare (ignore time))

(* -0.07 (- temperature 20)))

(defun euler (f y0 a b h)

"Euler's Method.

Approximates y(time) in y'(time)=f(time,y) with y(a)=y0 and t=a..b and the step size h."

(loop for time from a below b by h

for y = y0 then (+ y (* h (funcall f time y)))

do (format t "~6,3F ~6,3F~%" time y)))</lang>