Lee Mac Random Number Functions

Dear Lee,

Your code is a great.

But for intervals of negative shifts period by one.

(LM:randrange 1 3)
1
1
1
2
1
3
3
1
2
3

(LM:randrange -3 -1)
-1
-2
-1
-2
0
0
0
-2
0
-1

Of course, I can use a range of positive and negative transform him. I can also change the signs on the negative.

Please explain.

Please try the following [untested] modification:

;; Random in Range  -  Lee Mac
;; Returns a pseudo-random integral number in a given range (inclusive)

(defun LM:randrange ( a b )
   (+ (min a b) (fix (* (LM:rand) (1+ (abs (- a b))))))
)

EDIT: Updated.

I have now also updated the function on my site: Random in Range

Thanks for the update.

Sorry for my poor English language.

You're welcome Kowal, there is no need to apologise.

Hey Lee,

I ran into a problem with your random number generator as I attempted to use it in my acaddoc.lsp file. Because it seeds off the Date variable, the value is not random between opening files as they all begin at the same seed. each day. I was able to solve this by replacing your use of "getvar Date" with the MILLISECS variable and parsing it effectively to pull out the constantly changing base numbers. I now am able to successfully generate random numbers effectively in all use cases. I'm curious if you have encountered this problem before or may have a more elegant solution.

Thanks!

(setq old (rtos (getvar "MILLISECS") 2 0))

(setq new "")
(repeat (setq i (strlen old))
(setq new (strcat new (substr old i 1))
i (1- i)
)
)
(setq new (substr new 1 4))
(setq seed (atof new))