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

[arnold]

Hi.

Thanks to all who have replied.  I have updated the documentation
and will push it shortly.

Arnold

address@hidden wrote:

> 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
>