From: davidm@...
Date: 2014-10-13T03:48:41+00:00
Subject: [ruby-core:65640] [ruby-trunk - Feature #10225] [PATCH] *math.c: New method Math.normcdf

Issue #10225 has been updated by David MacMahon.


 On Oct 11, 2014, at 11:18 PM, mail@tanakakazuki.com wrote:
 
 > Sorry for my late. It's hard to say but.. ruby-gsl doesn't look good enough.
 
 I agree that ruby-gsl has its shortcomings.  GSL is a fairly large library that provides lots of functionality.  Exposing all that functionality to Ruby is no small task.  Another issue is memory management; I don't think GSL provides a way to hook into its memory allocation so that creates some issues.
 
 > And I suppose we'd better to make such a library from scratch.
 > 
 > (Actually I start to make other library(called Numrb)
 > 
 > Aside from that, I believe that providing such a feature "as standard" is really important in terms of reliability.
 
 I think I prefer a sort of middle ground.  I'd like some sort of "standard", built-in way of dealing with multidimensional numerical arrays.  I do not think we need to include loads of functionality out of the box, but it would be nice to have a standard multidimensional numerical array data type that different Ruby extensions could be created around.  IMHO, this would provide a nice modular approach so that things can evolve with a finer granularity.  It would somewhat decouple the numerical algorithms from the underlying data structures as well as provide for better interoperability between the different extensions that use multidimensional numerical arrays.
 
 > And we can make people we couldn't reach so far have interest in Ruby.
 
 It's always nice to broaden the appeal of Ruby!

----------------------------------------
Feature #10225: [PATCH] *math.c: New method Math.normcdf 
https://bugs.ruby-lang.org/issues/10225#change-49372

* Author: gogo tanaka
* Status: Open
* Priority: Normal
* Assignee: 
* Category: math
* Target version: current: 2.2.0
----------------------------------------
I know it looks kind of arbitrary or unnecessary feature ,but I believe that

to provide such a feature as official is helpful to make people we couldn't reach so far have interest in Ruby.

(Actually only this feature is not enough to do that..)

By the way I still wonder whether naming method make sense.

Debating between ...

```
Math::pnorm   -> R language use this
Math::phi     -> Euler's totient function is more popular as phi,
Math::ncdf
Math::guesscdf
Math::cdf_of_norm,
Math::cdf_of_guess
```

Finally I come to the conclusion Math::normcdf is most proper length, meaning and has no other worries.

---Files--------------------------------
_ math.c New method Math.normcdf.PATCH (1.04 KB)
_ test_math.rb Add tests for Math.normcdf.PATCH (609 Bytes)
_ NEWS About Math.normcdf.PATCH (488 Bytes)


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