FWIW, the Ruby/GSL gem already provides support for this (and many other =
things):

```
$ ruby -r gsl -e 'p GSL::Cdf::gaussian_P(1)'
0.8413447460685429
```

On Sep 10, 2014, at 11:26 PM, mail / tanakakazuki.com wrote:

> Issue #10225 has been reported by gogo tanaka.
>=20
> ----------------------------------------
> Feature #10225: [PATCH] *math.c: New method Math.normcdf=20
> https://bugs.ruby-lang.org/issues/10225
>=20
> * Author: gogo tanaka
> * Status: Open
> * Priority: Normal
> * Assignee:=20
> * Category:=20
> * Target version:=20
> ----------------------------------------
> I know it looks kind of arbitrary or unnecessary feature ,but I =
believe that
>=20
> to provide such a feature as official is helpful to make people we =
couldn't reach so far have interest in Ruby.
>=20
> (Actually only this feature is not enough to do that..)
>=20
> By the way I still wonder whether naming method make sense.
>=20
> Debating between ...
>=20
> ```
> 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
> ```
>=20
> Finally I come to the conclusion Math::normcdf is most proper length, =
meaning and has no other worries.
>=20
> ---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)
>=20
>=20
> --=20
> https://bugs.ruby-lang.org/