opmo Posted October 2, 2014 Share Posted October 2, 2014 To add a SEED to your own function and make it work you need to follow three simple rules: Add keyword SEED into the function arguments. (rnd-seed seed) should be placed at the beginning of the function. Nested functions that use seed need to use a (seed) function and not a seed argument. Example: (defun rnd-number (n low high &key seed) (do-verbose ("rnd-number") (rnd-seed seed) (if (zerop n) nil (cons (round (+ low (rnd-round 0 (- high low) :seed (seed)))) (rnd-number (decf n) low high :seed (seed)))))) Each time we evaluate the expression we get a different result. (rnd-number 12 0 5) => (0 3 2 5 3 3 4 3 2 2 4 4) Adding seed to the expression will produce always the same result. (rnd-number 12 0 5 :seed 45) => (2 2 5 4 5 0 5 3 5 3 1 1) Quote Link to comment Share on other sites More sharing options...
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