Bug in 3.0.1's betainc function (was Re: [OctDev] More than just an inconvenience Re: But in t_cdf: sporadic zero's when "no need")

[Dave Goel]

I have looked up matlab (TM)'s answers at a friend's workstation:

>
>> betainc (.75, 2047, .5)
>
> 4.437e-258

matlab: 4.437e-258

>
>> betainc (.85, 2047, .5)
>
> 0

matlab: 1.0659e-146


> ^^ If it returned a zero for .85, it should either do likewise for
> .75, or it should return a better answer for .85.
>
>
> ----

((Also, for x=3, 

> betainc (3,2047,.5)

matlab rightly returns an error demanding that x be in the interval
[0, 1]".  Octave does no such check, and returns with a convergence
error in a numerical function.))