RE: [sv-bc] $dist_ functions questions

Hi, Paul.

> Can anyone point me to information about the licence for using the C
> source code in the 1364-2005 LRM please?

[SB] I can't point you right now to an official statement, but I am sure that no license is required, just as no license is required for any other part of the standard, except possibly some of the optional encryption algorithms.

The code was donated by Cadence, which removed its copyright.
See http://boydtechinc.com/btf/archive/btf_1998/0194.html.

Note also that the code is not 64-bit portable, see http://www.boyd.com/1364_btf/report/full_pr/220.html.

 
> I also have a few remarks about these functions. t and chi_square have
> integral deg_of_freedom, whilst mathematically speaking I'd expect to be
> able to use reals.

[SB] I don't know why, but 20.15.2 is clear that deg_of_freedom is deliberately integral:

"The degree_of_freedom argument used with the $dist_chi_square and $dist_t functions is an integer
input that helps determine the shape of the density function. Larger numbers spread the returned values
over a wider range."

> There are imbalanced parentheses in rtl_dist_uniform
>
> r =(uniform(seed,start,end)+
> 2147483648.0)/4294967295.0);
>
> I'd say that the last closing parenthesis is superfluous.

[SB] Correct, thanks. This was a copy-paste error from the above 1998 email.

 
> If anyone is going to tidy this up, then I'd also suggest using ANSI
> function definitions rather than K&R,

[SB] I don't think anyone is going to touch this, except from fixing the parenthesis error.

> and including math.h rather than
> directly declaring pow and sqrt.

[SB] I don't see pow declared. Did you mean log()?

Regards,
Shalom
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