How can I round UP numbers instead of using FIX to round down?

[msirois]

I need to ALWAYS round a number up in my LISP routine. The fix command seems to only round down.

 

I need all numbers with any amount of decimal points to always round up to next even number. For example:

4.1 - round up to 5

5.8 - Round up to 6

3.00000000000001 - Round up to 4

2.00 - Stays the same; does not round up.

 

How can I do this easily?

Thanks in advance for the help.

 

A bit more info if needed:

 

I'm doing a stair LISP where I take the floor heights and divide it by 7 3/4" max riser height. Then that gives me a number of risers which needs to be round up to the next even number. I then take that number and divide up the difference in floor heights to create my risers.

[David Bethel]

For positive numbers maybe:

 

(if (/= (fix n) n)
   (setq n (1+ (fix n))))

 

-David

[msirois]

For positive numbers maybe:

 

(if (/= (fix n) n)
   (setq n (1+ (fix n))))

 

-David

 

Thank you. I however ended up using code from a post from LEE MAC. Here is what I used:

 

;;; Q is my variable that I needed round up
(defun ROUND ( n m )
   (cond
       ((equal 0.0 (rem n m) 1e- n)
       ((< n 0) (- n (rem n m)))
       ((+ n (- m (rem n m))))
   )
)

(setq B (ROUND Q 1))

[Lee Mac]

Just for variation, here is another for positive integers only:

(defun LM:int:roundup1 ( n ) (fix (+ n 1 -1e-))

_$ (LM:int:roundup1 2.1)
3

And for rounding up to any multiple:

(defun LM:int:roundup ( n m ) (* m (fix (+ (/ n (float m)) 1 -1e-)))

_$ (LM:int:roundup 4.3 2)
6

[msirois]

You are brilliant good sir.

[Lee Mac]

Thank you