[issue26114] Rewrite math.erf() and math.erfc() from scratch

Terry J. Reedy added the comment: Some additional history: the original 1986 book has separate copyright notices for text (Cambridge U Press), and computer programs (Numerical Recipes Software). It also has an offer to sell diskettes (Fortran or Pascal), 15 pounds each. There is no additiona

[issue26114] Rewrite math.erf() and math.erfc() from scratch

Changes by Brett Cannon : -- resolution: -> fixed stage: needs patch -> resolved status: open -> closed ___ Python tracker ___ ___ Py

[issue26114] Rewrite math.erf() and math.erfc() from scratch

Roundup Robot added the comment: New changeset faac8f09020d by Brett Cannon in branch '2.7': Issue #26114: Remove mention of 'Numerical Recipes'. https://hg.python.org/cpython/rev/faac8f09020d -- ___ Python tracker

[issue26114] Rewrite math.erf() and math.erfc() from scratch

Roundup Robot added the comment: New changeset 76eb752e5447 by Brett Cannon in branch '3.5': Issue #26114: Remove a reference to 'Numerical Recipes'. https://hg.python.org/cpython/rev/76eb752e5447 New changeset 8ad701463cd7 by Brett Cannon in branch 'default': Merge for issue #26114 https://hg.p

[issue26114] Rewrite math.erf() and math.erfc() from scratch

Brett Cannon added the comment: Thanks for the historical information, Mark! I'll either update the comment or flat-out delete it so it doesn't trip anyone else up. I'll also scale back the scope of the update since it's just a cleanup and not an IP issue. -- assignee: -> brett.canno

[issue26114] Rewrite math.erf() and math.erfc() from scratch

Mark Dickinson added the comment: @Serhiy: Sure, that would work (the same way that we do for log1p). I *think* I tried this at the time, but it turns out that some libm implementations of erf and erfc are pretty bad, so our tests failed. (But I may be misremembering.) In any case, the proposa

[issue26114] Rewrite math.erf() and math.erfc() from scratch

Marc-Andre Lemburg added the comment: On 15.01.2016 10:05, Mark Dickinson wrote: > > Mark Dickinson added the comment: > > ... and the way I read it, the NR licence applies specifically to their code, > not to the basic numerical ideas set out in the text (which is all we're > using). We're n

[issue26114] Rewrite math.erf() and math.erfc() from scratch

Serhiy Storchaka added the comment: erf() is a part of C99. May be move hand-writen implementation to Modules/_math.c and use libc erf() if available? -- nosy: +serhiy.storchaka ___ Python tracker

[issue26114] Rewrite math.erf() and math.erfc() from scratch

Mark Dickinson added the comment: ... and the way I read it, the NR licence applies specifically to their code, not to the basic numerical ideas set out in the text (which is all we're using). We're not using the actual code from NR at all. IOW, IANAL but I really don't think there's an issue

[issue26114] Rewrite math.erf() and math.erfc() from scratch

Mark Dickinson added the comment: The comment is unfortunate. The code in Modules/mathmodule.c *was* written from scratch (by me). All I took from Numerical Recipes was the idea of using continued fractions from one part of the domain and a power-series expansion for another part. If you compa

[issue26114] Rewrite math.erf() and math.erfc() from scratch

Changes by STINNER Victor : -- nosy: +haypo ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python

[issue26114] Rewrite math.erf() and math.erfc() from scratch

Changes by Brett Cannon : -- nosy: -peter ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.

[issue26114] Rewrite math.erf() and math.erfc() from scratch

Changes by Brett Cannon : -- nosy: +peter, teoliphant ___ Python tracker ___ ___ Python-bugs-list mailing list Unsubscribe: https://m

[issue26114] Rewrite math.erf() and math.erfc() from scratch

New submission from Brett Cannon: If you look Modules/mathmodule.c you will notice there is a comment that goes with erf() and erfc() stating that the algorithms were taken from a book entitled 'Numerical Recipes'. Unfortunately that book has a license dictating that any information from the b