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  • Another "Kernel connection has been lost"

    From Peter Luschny@21:1/5 to All on Mon Sep 25 01:24:33 2017
    restart;
    with(gfun):
    L:=[seq(bernoulli(n),n=0..13)];
    guessgf(L,x,['egf']);

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From acer@21:1/5 to Peter Luschny on Mon Sep 25 12:20:15 2017
    On Monday, September 25, 2017 at 4:24:35 AM UTC-4, Peter Luschny wrote:
    restart;
    with(gfun):
    L:=[seq(bernoulli(n),n=0..13)];
    guessgf(L,x,['egf']);

    In each version I looked at since Maple 17.00 (Feb, 2013) that has returned FAIL in a few seconds.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Peter Luschny@21:1/5 to All on Tue Sep 26 14:11:24 2017
    In each version I looked at since Maple 17.00 (Feb, 2013) that has returned FAIL in a few seconds.

    That's good news, because it means that it doesn't make sense to order an upgrade
    because of this bug.

    On the other hand, not being able to recover the most famous generating function
    of all from the Bernoulli numbers is a bit depressing.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From acer@21:1/5 to Peter Luschny on Fri Sep 29 08:34:20 2017
    On Tuesday, September 26, 2017 at 5:11:25 PM UTC-4, Peter Luschny wrote:
    In each version I looked at since Maple 17.00 (Feb, 2013) that has returned FAIL in a few seconds.

    That's good news, because it means that it doesn't make sense to order an upgrade
    because of this bug.

    On the other hand, not being able to recover the most famous generating function
    of all from the Bernoulli numbers is a bit depressing.


    Isn't the gfun package designed for holonomic functions?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Peter Luschny@21:1/5 to All on Sat Sep 30 05:36:23 2017
    Isn't the gfun package designed for holonomic functions?

    Read the docs by Maplesoft, they do not indicate this (and they
    certainly should if the function is restricted to this case):

    https://fr.maplesoft.com/support/help/Maple/view.aspx?path=gfun/guessgf

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From acer@21:1/5 to Peter Luschny on Mon Oct 2 13:02:16 2017
    On Saturday, September 30, 2017 at 8:36:24 AM UTC-4, Peter Luschny wrote:
    Isn't the gfun package designed for holonomic functions?

    Read the docs by Maplesoft, they do not indicate this (and they
    certainly should if the function is restricted to this case):

    https://fr.maplesoft.com/support/help/Maple/view.aspx?path=gfun/guessgf


    I agree that such a restriction (if it is the case) should be mentioned explicitly.

    It's possible that I am missing something about the functionality, however.

    Reading the help-page for `guessgf` from the `gfun` package, it says that the command attempts three things:

    1) "Tries to find a rational function..."
    2) "Tries to find a hypergeometric functions..." (via the `listtohypergeom` command in the `gfun` package, which discusses 2F1)
    3) "Tries to find a linear differential equation with polynomial coefficients."

    Which of those do you think might produce a generating function with infinitely many complex singularities? [ not number 3)... ] If none then the information is there implicitly.

    See also,
    https://en.wikipedia.org/wiki/Holonomic_function#Examples_of_nonholonomic_functions_and_sequences

    https://en.wikipedia.org/wiki/Holonomic_function#cite_note-4

    https://www.maplesoft.com/support/help/Maple/view.aspx?path=gfun%2flisttohypergeom

    https://en.wikipedia.org/wiki/Holonomic_function#Algorithms_and_software


    The site of the author of the `gfun` package is here:

    It says, "The primary reference to use when citing gfun is the following one:

    B. Salvy and P. Zimmermann, “Gfun: a Maple package for the manipulation of generating and holonomic functions in one variable,” toms, vol. 20, no. 2, pp. 163–177, 1994."

    Unfortunately I don't see change-notes for the various point-releases of the package on that site, so I cannot point to descriptions of how it may have changed over the years.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)