OpenEuphoria

Re: bug in remainder ?

• Posted by Everett Williams <rett at GVTC.COM> Feb 03, 2000
• 415 views

On Thu, 3 Feb 2000 16:19:45 -0500, Brian Broker <bkb at CNW.COM> wrote:

>On Thu, 3 Feb 2000 16:09:48 -0500, Brian Broker <bkb at CNW.COM> wrote:
>
>>On Thu, 3 Feb 2000 20:21:04 +0000, Daniel Johnson wrote:
>>
>>>? remainder(1,.1)
>>>.1
>>>? remainder(1,.01)
>>>.01
>>>? remainder(10,1)
>>>1
>>
>>I get:
>>0.1
>>0.01
>>0
>
>Hmmm... now that I think about it, shouldn't they all be zero?  What am I
>missing here?
>
>? remainder( 3.5, 1.7 )
>for example, correctly outputs 0.1
>
>-- Brian

Here's the definition from the manual

Syntax:
x3 = remainder(x1, x2)
Description:
Compute the remainder after dividing x1 by x2. The result will have the same
sign as x1, and the magnitude of the result will be less than the magnitude of
x2.
Comments:
The arguments to this function may be atoms or sequences. The rules for
operations on sequences apply.

By this, any even multiple should provide an answer of zero, but if an
enterprising interpreter were to convert .01 or any other decimal value
less than 0 to a float before doing the the division, the answer
would always come out slightly different than one would expect because of
rounding errors. To get an accurate value, one must move the decimal on
both the divisor and the dividend so that both are whole numbers and then
scale the remainder.

 ? remainder(10,1)/10
 0
 ? remainder(100,1)/100
 0
 ? remainder(10,1)
 0

Everett L.(Rett) Williams
rett at gvtc.com