Re: [bug-gawk] Error Gawk Manual FP Precision

[arnold]

Hi.

Thanks for your note.  In the future, PLEASE send in plain text
format, not HTML, or at the very least, text and HTML.

Thanks.

On to your note:

> Dear bug-gawk:
>
> The section on comparing two floating point values correctly recommends
> making avoiding simple equality comparisons in favor of ensuring the
> values are close enough.
>
> The code given in 15.4.1.2 "Be Careful Comparing Values" is clearly
> wrong, though:
> 
>       The general wisdom when comparing floating-point values is to see
>       if they are within some small range of each other (called a delta,
>       or tolerance).  You have to decide how small a delta is important
>       to you.  Code to do this looks something like the following:
>             
>             delta = 0.00001                 # for example
>             difference = abs(a) - abs(b)    # subtract the two values
>             if (difference < delta)
>                 # all ok
>             else
>                 # not ok
>
> If the desired value, a is -1000, and b is +1000, the answer is off by
> 2000. But difference will be zero.

You are correct. I will look at revising the documentation.

Thanks for pointing this out.

Arnold