Cantor 17.12 crashes working with R and Sage backends and is very slow with some other ones on Arch Linux.

Sat Jan 13 10:32:23 UTC 2018

Hello Fernando,

thank you for your warm words about KDE and Cantor :-)

The connection to and the initialization of a backend process takes some 
time. The times are different for different backends.
Your observations about the long evaluation times for the first 
expression and almost instant evaluation of the subsequent expressions
is because of the recent improvement that was done in 17.12. Previously, 
the initialization was done during the creation of a new session.
So, when opening a project file the user had to wait until the 
initialization is done even in cases where he/she doesn't plan to modify 
the worksheet at all.
This was changed. The creation of a new session or opening of saved 
project files is much faster now and the initialization of the backend 
process is
postponed to the point when the user really asks Cantor to evaluate 
something.

The recommended versions for R and Sage are missing, yes. But those are 
minor issues compared to the crashes you have. Let's have a look at them 
first.
Which versions of Maxima and Sage are you using? Any chance to install 
the debuginfo package for Cantor and to try again? Without the debug symbols
the crash dumps are not really useful...

Connection to R is broken, the fix for this is "work in progress" at the 
moment.

Regards,
Alexander

On 12.01.2018 19:20, Fernando de Morais wrote:
> Hello Alexander,
>
> Thank you for a fast reply. I'll do my best to describe my problems:
>
> 1 - The first strange behavior that I noticed is Cantor not showing 
> the recommended version for R and Sage (Pic 1 and 2) :
>
>
>
> 
>
>     1.1 - It opposes for other backends (Pic 3 and 4):
>
>
> 
> 2 - When I choose Sage as my backend and try to calculate any sheet I 
> face a crash (Pic 5):
>
>
>
>     2.1 - I generated the "backtrace" file using drkonqi tool (attach_1).
>
>
> 3 - The same behavior mentioned before occurs when I run any 
> calculation with Maxima backend (Pic 6):
>
>
>
>     3.1 - Again, I generated the "backtrace" file using drkonqi tool
>     (attach_2).
>
>
> 4 - About the slowness, I tested all the backends and marked the time 
> (Ktimer) needed for Cantor show me the output. I use a simple "2+2" 
> operation:
>
>   * Julia: takes exactly 60 seconds to show the result (every simple
>     calculation that I've tried);
>   * KAlgebra: instantly shows the result;
>   * Lua (LuaJIT): instantly shows the result;
>   * Maxima: crashes like I said in section 3 of this e-mail;
>   * Octave: circa 15 seconds to show the result (only in the first
>     calculation of the section. Other simple calculations are
>     instantly load);
>   * Python 2: circa 10~11 seconds to show the result (only in the
>     first calculation of the section. Other simple calculations are
>     instantly load);
>   * Python 3: circa 5 seconds to show the result (only in the first
>     calculation of the section. Other simple calculations are
>     instantly load);
>   * Qalculate!: instantly shows the result;
>   * R: never shows the result. I waited about 15 minutes and nothing.
>     Cantor doesn't crash, but I have to close the software to use it
>     again.
>   * Sage: crashes like I said in section 2 of this e-mail;
>   * Scilab: I can't do any test with this backend because it is still
>     unstable on Arch Linux, so I did not install it.
>
>     4.1 - All backends used is properly installed on my system
>     (attach_3), with all dependencies satisfied; all backends are
>     properly configured in Cantor; and the follow pic shows my system
>     details (Pic 7):
>
>
>
>     
>
> Well, I think this is a more accurate report that I can do by now.
>
> I love KDE (Qt stuff in general) and its applications, and I use them 
> because I feel more productive with them. Cantor is a tool that I 
> love, and one of the reasons for me migrate to KDE back in 2016. In 
> that time I was using Debian GNU/Linux, but since I met Arch, I can't 
> leave him.
>
> PS.: As I said before I'm a Arch Linux user, and I don't know if its a 
> system specific problem, but it may be difficult for this to be the 
> reason, because its a rolling release distro, so I use the latest 
> stable packages.
>
> I like to thank all the support. Sorry for a long e-mail.
>
> Best regards.
>
> -- 
> Atenciosamente,
> *José Fernando de Morais Firmino.
> *
> Graduando no Curso Superior de Tecnologia em Automação Industrial.
> *IFPB,* Campus Cajazeiras.
> Currículo Lattes: clique aqui <http://lattes.cnpq.br/0001199049062038>.
> Diretório de Grupos de Pesquisa: clique aqui 
> <http://dgp.cnpq.br/dgp/espelhorh/0001199049062038>.
> E-mail acadêmico: fernando.morais at academico.ifpb.edu.br 
> <mailto:fernando.morais at academico.ifpb.edu.br>

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