| msg222067 - (view) |
Author: Kevin Davies (kdavies4) |
Date: 2014-07-02 04:31 |
| The docstring of acosh should more accurately be "Return the area hyperbolic cosine of x." instead of "Return the hyperbolic arc cosine (measured in radians) of x." asinh and atanh should be changed similarly. The result of these functions is not an angle but a ratio of areas. See http://en.wikipedia.org/wiki/Inverse_hyperbolic_function. |
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| msg222068 - (view) |
Author: Ezio Melotti (ezio.melotti) *  |
Date: 2014-07-02 04:47 |
| Do you want to propose a patch? https://docs.python.org/3/library/math.html#hyperbolic-functions should be updated as well. |
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| msg222072 - (view) |
Author: Mark Dickinson (mark.dickinson) * |
Date: 2014-07-02 06:24 |
| How about simply 'inverse hyperbolic cosine', etc. I think that's more likely to be immediately obvious to readers. |
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| msg222073 - (view) |
Author: Mark Dickinson (mark.dickinson) * |
Date: 2014-07-02 06:26 |
| and the 'radians' bit is obviously nonsense. |
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| msg222076 - (view) |
Author: Kevin Davies (kdavies4) |
Date: 2014-07-02 07:10 |
| Unfortunately I'm not currently set up with Mercurial and I'm not sure that it makes sense to get that going just for this. On 07/01/2014 06:47 PM, Ezio Melotti wrote: > Ezio Melotti added the comment: > > Do you want to propose a patch? > https://docs.python.org/3/library/math.html#hyperbolic-functions should be updated as well. > > ---------- > assignee: -> docs@python > components: +Documentation > keywords: +easy > nosy: +docs@python, ezio.melotti, mark.dickinson, rhettinger, stutzbach > stage: -> needs patch > type: -> enhancement > versions: +Python 2.7, Python 3.4, Python 3.5 > > _______________________________________ > Python tracker <report@bugs.python.org> > <http://bugs.python.org/issue21902> > _______________________________________ > |
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| msg222077 - (view) |
Author: Mark Dickinson (mark.dickinson) * |
Date: 2014-07-02 07:12 |
| Here's a patch. |
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| msg222078 - (view) |
Author: Mark Dickinson (mark.dickinson) * |
Date: 2014-07-02 07:13 |
| Ezio: > https://docs.python.org/3/library/math.html#hyperbolic-functions should be updated as well. It looks fine to me. What do you think should be changed? |
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| msg222079 - (view) |
Author: Kevin Davies (kdavies4) |
Date: 2014-07-02 07:14 |
| Yes, 'inverse' is probably more obvious to understand than 'area', although it doesn't tie into the 'a' of 'acosh', etc. On 07/01/2014 08:24 PM, Mark Dickinson wrote: > Mark Dickinson added the comment: > > How about simply 'inverse hyperbolic cosine', etc. I think that's more likely to be immediately obvious to readers. > > ---------- > > _______________________________________ > Python tracker <report@bugs.python.org> > <http://bugs.python.org/issue21902> > _______________________________________ > |
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| msg222082 - (view) |
Author: Mark Dickinson (mark.dickinson) * |
Date: 2014-07-02 07:44 |
| Kevin: does the attached patch look okay to you? |
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| msg222083 - (view) |
Author: Mark Dickinson (mark.dickinson) * |
Date: 2014-07-02 07:46 |
| Updated patch, fixing an accidental double space in the previous one. |
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| msg222089 - (view) |
Author: Ezio Melotti (ezio.melotti) * |
Date: 2014-07-02 09:18 |
| >> https://docs.python.org/3/library/math.html#hyperbolic-functions should be updated as well. > > It looks fine to me. What do you think should be changed? I just meant to say that the docs and the docstrings should be kept in sync (especially if they are short like in this case). If the definition in the docs is better it could be used for the docstrings; if something gets improved in the docstring that is not already in the docs it should be added to the docs as well. If either one is fine there's no need to update it. |
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| msg222091 - (view) |
Author: Kevin Davies (kdavies4) |
Date: 2014-07-02 09:41 |
| Mark: The patch looks good. Thanks! |
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| msg222271 - (view) |
Author: Raymond Hettinger (rhettinger) * |
Date: 2014-07-04 08:13 |
| > inverse' is probably more obvious to understand than 'area', > although it doesn't tie into the 'a' of 'acosh', etc. Please don't make this gratuitous change. The decision about whether to use "inverse" or "arc" was cast in stone when the functions were named "acosh" etc. The documentation for C's math.h uses "arc". The docs for my hand calculators all use the term "arc" in the description of what the keys do. Why create unnecessary divergence? If you truly think users of acosh can't cope with "arc", then add a clarifying parenthetical for "inverse". But don't make the function name "acosh" more opaque by not showing what it actually stands for. |
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| msg222285 - (view) |
Author: Mark Dickinson (mark.dickinson) * |
Date: 2014-07-04 14:12 |
| Raymond: I don't think it's gratuitous. I'd be happy to replace the 'inverse' by 'area' if that's what people prefer. But "hyperbolic arc cosine" is just plain incorrect. (And the "in radians" bit is utterly nonsensical.) |
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| msg222329 - (view) |
Author: Raymond Hettinger (rhettinger) * |
Date: 2014-07-05 01:36 |
| > I'd be happy to replace the 'inverse' by 'arc' > if that's what people prefer. Yes, please. > And the "in radians" bit is utterly nonsensical Yes, again. |
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| msg222335 - (view) |
Author: Kevin Davies (kdavies4) |
Date: 2014-07-05 04:47 |
| I'm not sure what the resolution is (the patch was 'inverse', Mark said he'd be happy to use 'area', and Raymond quoted 'arc'). I didn't know this would be a big deal, and I'm sorry that I caused trouble. But since one of the concerns was divergence, I thought I'd send some info on how the tools I've used describe it -- universally as 'inverse' in those that I found: - Mathematica: ArcCosh[z] "gives the inverse hyperbolic cosine [...]" (http://reference.wolfram.com/mathematica/ref/ArcCosh.html) - Modelica Standard Library: acosh "Inverse of cosh (area hyperbolic cosine)" (http://reference.wolfram.com/system-modeler/libraries/Modelica/Modelica_Math_acosh.html) - Maple: arccosh, but unknown description (http://www.maplesoft.com/support/help/Maple/view.aspx?path=invtrig) - MATLAB: acosh " Inverse hyperbolic cosine" (http://www.mathworks.com/help/matlab/ref/acosh.html) - TI-89 calculator: cosh-1 "returns the inverse hyperbolic cosine [...]" (from manual) Respectfully, Kevin |
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| msg222336 - (view) |
Author: Tim Peters (tim.peters) * |
Date: 2014-07-05 06:12 |
| One more useless ;-) data point, from Macsyma: ? acosh; -- Function: acosh () - Hyperbolic Arc Cosine. I don't like "area" - while accurate, nobody else uses it. Gratuitous novelty is no virtue ;-) I like "inverse" better than "arc", because it's all of accurate, common, and nearly self-evident. |
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| msg233846 - (view) |
Author: Roundup Robot (python-dev)  |
Date: 2015-01-11 13:03 |
| New changeset d81cabb39de3 by Mark Dickinson in branch '2.7': Issue #21902: Replace incorrect 'hyperbolic arc sine' (etc.) with 'inverse hyperbolic sine' (etc.). Remove meaningless reference to radians. https://hg.python.org/cpython/rev/d81cabb39de3 |
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| msg233848 - (view) |
Author: Roundup Robot (python-dev) |
Date: 2015-01-11 13:23 |
| New changeset 5edfc6c929f9 by Mark Dickinson in branch '3.4': Issue #21902: Replace incorrect 'hyperbolic arc sine' (etc.) with 'inverse hyperbolic sine' (etc.). Remove meaningless reference to radians. https://hg.python.org/cpython/rev/5edfc6c929f9 |
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| msg233850 - (view) |
Author: Mark Dickinson (mark.dickinson) * |
Date: 2015-01-11 13:28 |
| Roundup message copied from #21902 (bad issue number): New changeset 36099a05d76a by Mark Dickinson in branch 'default': Issue #21092: Merge from 3.4. https://hg.python.org/cpython/rev/36099a05d76a |
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| msg233851 - (view) |
Author: Mark Dickinson (mark.dickinson) * |
Date: 2015-01-11 13:29 |
| Closing as fixed. |
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