| Re: what is Floating illegal operand question? [message #43689 is a reply to message #43687] |
Mon, 18 April 2005 14:51   |
Michael Wallace
Messages: 409
Registered: December 2003
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Senior Member |
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(0 / 0) is just as undefined as (0.0 / 0.0) is. However, there is no
way to express NaN or Infinity when working with integers. The IEEE
floating point specification allows for NaN and Infinity, but the
integer spec does not. Without a NaN option, IDL (and other languages
as well), default to evaluating (0 / 0) as 0 even though this is
technically incorrect.
-Mike
Haje Korth wrote:
> Well, if I understand this right, 0/0 is defined and the result is 0, so
> that the division by zero message is only informational. On the other hand
> 0./0. is not defined for floating point numbers and results in an error (see
> http://mathworld.wolfram.com/DivisionbyZero.html). Correct me if I am wrong.
>
> Haje
>
>
>> You're getting it from a floating point divide by zero. When using
>> integers, IDL actually tells you that you tried to divide by zero. For
>> some reason, they have a different message for floating point.
>>
>> IDL> x = 0 / 0
>> % Program caused arithmetic error: Integer divide by 0
>> IDL> x = 0.0 / 0.0
>> % Program caused arithmetic error: Floating illegal operand
>>
>> -Mike
>
>
>
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