Re: laguerre.m functions in specfun package

[Juan Pablo Carbajal]

On Tue, Apr 28, 2015 at 6:30 PM, Carnë Draug <address@hidden> wrote:
> On 25 April 2015 at 20:30, Philip Nienhuis <address@hidden> wrote:
>> Carnë Draug wrote:
>>>
>>> On 25 April 2015 at 15:56, Philip Nienhuis <address@hidden>
>>> wrote:
>>>>
>>>> After Colin has tidied up a bit in the OF specfun package, I'm planning
>>>> to
>>>> make a new release of it.
>>>>
>>>> The package in the mercurial repo contains two laguerre.m functions, one
>>>> in
>>>> inst/, the other in devel/
>>>>
>>>> The latter looks to be a bit more elaborate (it contains a demo and
>>>> perhaps
>>>> more aptly named variables), to compensate for that it is lacking a bit
>>>> in
>>>> coding style and lacks the one comment line that was present in the
>>>> original
>>>> (?) one in inst/.
>>>>
>>>> So, any advice about which laguerre.m to retain?
>>>
>>>
>>> "hg log" tells me this is work from Juan Carbajal who was trying to merge
>>> the
>>> existing laguerre with laguerrepoly from the miscellaneous package:
>>>
>>>      o  changeset:   144:88d235233c5e
>>>      |  user:        jpicarbajal
>>>      |  date:        Sun Apr 14 19:33:57 2013 +0000
>>>      |  files:       devel/laguerre.m
>>>      |  description:
>>>      |  specfun: unifying laguerre and laguerrepoly
>>>
>>> Also, the plan was to simply move the whole specfun package into the
>>> unmaintained section.
>>>
>>> https://savannah.gnu.org/bugs/?44533#comment3
>>
>>
>> Hmmm, I missed that part of the discussion (although I commented there
>> initially).
>>
>> I wouldn't mind keeping specfun around a little longer, esp. now that Colin
>> pimped the heaviside and dirac functions.
>> His suggestion to move them to core is probably too late for 4.0.0 so I
>> suggested to temporarily have them in a new specfun release, see
>> https://savannah.gnu.org/patch/index.php?8644#comment4
>>
>> As far as I'm concerned that could be the last specfun release then; it
>> could have a dependency added on Octave < 4.2.0
>>
>> So, what shall I do?
>
> I am arguing that dirac and heaviside should be moved to the symbolic
> package.  And then we drop the specfun package.
> See https://savannah.gnu.org/patch/?8644#comment13
>
> Carnë
>

I completely disagree with this.
Symbolic does not offer replacement for these functions. Specially it
is not true that

multinom, multinom_coeff, multinom_exp -- I think these are monomials,
and nthcoeff in the sym,bolic package

(mind the "I think"). These functions are optimized for numeric not
for symbolic manipulation (which by the way is the main role of
octave). The symbolic version of these function will just ad an over
heard in time execution and memory!

Please always think of this when you want to replace a numerical
version of a function with a symbolic one (please!). You should
provide performance (time and memory) justifying the change.

In any case, if you want to get rid of specfun (I do not know why you
would want that!), I would say be mindful if your are not a user of
the package. Your interest might not coincide with the interest of the
true/intended users.