ROUND UP A NUMBER.

Using lisp, how would I go about rounding up a number (real) to the nearest
whole number (integer)

Thanks

Casey

 

Actually, upon further investigation, I want the result to be a whole
number, but not an integer as there seems to be some issues with dividing by
a real number.

 

so do you want 1.01 to be rounded up to 2.0 ???
or is only 1.5 rounded up to 2.0???
your original question would seem to imply the first case, but in the real
world that would be unusual
so it depends on *exactly* what you need to accomplish

what about negative numbers?
does round up mean become more negative????

there are lots of unknowns based solely on your question as stated.
Can you elaborate somewhat?

The rounding operation would probably be quite easy to implement, but it
depends on what you really need.

Mark

 

(atoi (rtos (+ test 0.5) 2 0))

 

(atof (rtos (+ number 0.5) 2 0))

 

For example,
If I interpret your question literally, this would be what I'd try.
(defun roundx(num)
(* 1.0(1+ (Fix num)))
)

maybe what you want or may not be what you want
Hth
Mark

 

Call me simple, but I always did it this way:

Code:

(defun rndup (real)
(float (fix (+ 0.99999999 real)))
)

(defun c:test ()
(print (rndup 1.01))
(print (rndup 1.05))
(print (rndup 1.99999))
(print (rndup 0.9999))
(print (rndup -2.01))
(princ)
)

Command: test

2.0
2.0
2.0
1.0
-1.0

 

You could handle negative numbers this way.

Code:

(defun rndup (num)
(if (>= num 0)
(float (fix (+ 0.99999999 num)))
(float (fix num))
)
)

(defun c:test ()
(print (rndup 1.01))
(print (rndup 1.05))
(print (rndup 1.99999))
(print (rndup 0.9999))
(print (rndup -2.01))
(print (rndup -0.01))
(princ)
)

Command: test

2.0
2.0
2.0
1.0
-2.0
0.0

 

This will round negative numbers up if the are >=.5

Code:

(defun rndup (num)
(if (>= num 0)
(float (fix (+ 0.5 num)))
(float (fix (- num 0.5)))
)
)

(defun c:test ()
(print (rndup 1.01))
(print (rndup 1.05))
(print (rndup 1.99999))
(print (rndup 0.9999))
(print (rndup 0.49))
(print (rndup -2.01))
(print (rndup -0.01))
(print (rndup -0.6))
(princ)
)

Command: test

1.0
1.0
2.0
1.0
0.0
-2.0
0.0
-1.0

 

Yanked this one out of the toolbox.

; Doug Broad
; additional credits Joe Burke, Peter Toby
(defun round (value to)
(setq to (abs to))
(* to (fix (/ ((if (minusp value) - +) value (* to 0.5)) to)))
)

 

Except for one problem. This rounds 1.0 up to 2, which is not correct.

To clarify, from my first posts, I don't have to deal with negative numbers
and yes, 1.01 should round up to 2, but 1.0 should remain 1.0.

What I came up with is:
(if (/= num (fix num))(setq num (+ 1.0 (fix num))))

 

cool, glad you got a solution

Mark