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

Fernando de Morais fernandodemorais.jf at gmail.com
Fri Jan 12 18:20:56 UTC 2018 

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
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Application: Cantor (cantor), signal: Segmentation fault
Using host libthread_db library "/usr/lib/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f7d3296cc80 (LWP 7779))]

Thread 3 (Thread 0x7f7d16b7f700 (LWP 7781)):
#0  0x00007f7d2eaa93d8 in read () from /usr/lib/libc.so.6
#1  0x00007f7d28fe3831 in ?? () from /usr/lib/libglib-2.0.so.0
#2  0x00007f7d28f9db28 in g_main_context_check () from /usr/lib/libglib-2.0.so.0
#3  0x00007f7d28f9dff6 in ?? () from /usr/lib/libglib-2.0.so.0
#4  0x00007f7d28f9e16e in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#5  0x00007f7d2f60f6b4 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#6  0x00007f7d2f5b182b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#7  0x00007f7d2f3c178e in QThread::exec() () from /usr/lib/libQt5Core.so.5
#8  0x00007f7d2b93c416 in ?? () from /usr/lib/libQt5DBus.so.5
#9  0x00007f7d2f3c6b2d in ?? () from /usr/lib/libQt5Core.so.5
#10 0x00007f7d2b09b08c in start_thread () from /usr/lib/libpthread.so.0
#11 0x00007f7d2eab7e1f in clone () from /usr/lib/libc.so.6

Thread 2 (Thread 0x7f7d202bb700 (LWP 7780)):
#0  0x00007f7d2eaad91b in poll () from /usr/lib/libc.so.6
#1  0x00007f7d28d368e0 in ?? () from /usr/lib/libxcb.so.1
#2  0x00007f7d28d38679 in xcb_wait_for_event () from /usr/lib/libxcb.so.1
#3  0x00007f7d230697aa in ?? () from /usr/lib/libQt5XcbQpa.so.5
#4  0x00007f7d2f3c6b2d in ?? () from /usr/lib/libQt5Core.so.5
#5  0x00007f7d2b09b08c in start_thread () from /usr/lib/libpthread.so.0
#6  0x00007f7d2eab7e1f in clone () from /usr/lib/libc.so.6

Thread 1 (Thread 0x7f7d3296cc80 (LWP 7779)):
[KCrash Handler]
#5  0x00007f7d2f52dbf4 in QProcess::pid() const () from /usr/lib/libQt5Core.so.5
#6  0x00007f7d30cba6ea in KProcess::pid() const () from /usr/lib/libKF5CoreAddons.so.5
#7  0x00007f7d04bb39eb in ?? () from /usr/lib/qt/plugins/cantor/backends/cantor_sagebackend.so
#8  0x00007f7d04bb4810 in ?? () from /usr/lib/qt/plugins/cantor/backends/cantor_sagebackend.so
#9  0x00007f7d04bb10a0 in ?? () from /usr/lib/qt/plugins/cantor/backends/cantor_sagebackend.so
#10 0x00007f7d040a4cbe in ?? () from /usr/lib/qt/plugins/libcantorpart.so
#11 0x00007f7d0409933b in ?? () from /usr/lib/qt/plugins/libcantorpart.so
#12 0x00007f7d040e356e in ?? () from /usr/lib/qt/plugins/libcantorpart.so
#13 0x00007f7d2f5e3a06 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQt5Core.so.5
#14 0x00007f7d30327383 in QAction::triggered(bool) () from /usr/lib/libQt5Widgets.so.5
#15 0x00007f7d30329c06 in QAction::activate(QAction::ActionEvent) () from /usr/lib/libQt5Widgets.so.5
#16 0x00007f7d30424c1c in ?? () from /usr/lib/libQt5Widgets.so.5
#17 0x00007f7d30424e8e in QAbstractButton::mouseReleaseEvent(QMouseEvent*) () from /usr/lib/libQt5Widgets.so.5
#18 0x00007f7d3050addb in QToolButton::mouseReleaseEvent(QMouseEvent*) () from /usr/lib/libQt5Widgets.so.5
#19 0x00007f7d3036de38 in QWidget::event(QEvent*) () from /usr/lib/libQt5Widgets.so.5
#20 0x00007f7d3050ae75 in QToolButton::event(QEvent*) () from /usr/lib/libQt5Widgets.so.5
#21 0x00007f7d3032de3c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#22 0x00007f7d30335d91 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#23 0x00007f7d2f5b31e0 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/libQt5Core.so.5
#24 0x00007f7d30334d1a in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool) () from /usr/lib/libQt5Widgets.so.5
#25 0x00007f7d30389289 in ?? () from /usr/lib/libQt5Widgets.so.5
#26 0x00007f7d3038b9a0 in ?? () from /usr/lib/libQt5Widgets.so.5
#27 0x00007f7d3032de3c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#28 0x00007f7d30335816 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#29 0x00007f7d2f5b31e0 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/libQt5Core.so.5
#30 0x00007f7d2fb24634 in QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) () from /usr/lib/libQt5Gui.so.5
#31 0x00007f7d2fb26186 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () from /usr/lib/libQt5Gui.so.5
#32 0x00007f7d2fafdbbc in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Gui.so.5
#33 0x00007f7d230f128d in ?? () from /usr/lib/libQt5XcbQpa.so.5
#34 0x00007f7d2f5b182b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#35 0x00007f7d2f5bab18 in QCoreApplication::exec() () from /usr/lib/libQt5Core.so.5
#36 0x000055f4a189586c in ?? ()
#37 0x00007f7d2e9e2f4a in __libc_start_main () from /usr/lib/libc.so.6
#38 0x000055f4a1895fca in _start ()
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Application: Cantor (cantor), signal: Segmentation fault
Using host libthread_db library "/usr/lib/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fb2baaa4c80 (LWP 8015))]

Thread 3 (Thread 0x7fb29e6d6700 (LWP 8017)):
#0  0x00007fb2b6be13d8 in read () at /usr/lib/libc.so.6
#1  0x00007fb2b111b831 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007fb2b10d5b28 in g_main_context_check () at /usr/lib/libglib-2.0.so.0
#3  0x00007fb2b10d5ff6 in  () at /usr/lib/libglib-2.0.so.0
#4  0x00007fb2b10d616e in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#5  0x00007fb2b77476b4 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#6  0x00007fb2b76e982b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#7  0x00007fb2b74f978e in QThread::exec() () at /usr/lib/libQt5Core.so.5
#8  0x00007fb2b3a74416 in  () at /usr/lib/libQt5DBus.so.5
#9  0x00007fb2b74feb2d in  () at /usr/lib/libQt5Core.so.5
#10 0x00007fb2b31d308c in start_thread () at /usr/lib/libpthread.so.0
#11 0x00007fb2b6befe1f in clone () at /usr/lib/libc.so.6

Thread 2 (Thread 0x7fb2a83f3700 (LWP 8016)):
#0  0x00007fb2b6be591b in poll () at /usr/lib/libc.so.6
#1  0x00007fb2b0e6e8e0 in  () at /usr/lib/libxcb.so.1
#2  0x00007fb2b0e70679 in xcb_wait_for_event () at /usr/lib/libxcb.so.1
#3  0x00007fb2ab1a17aa in  () at /usr/lib/libQt5XcbQpa.so.5
#4  0x00007fb2b74feb2d in  () at /usr/lib/libQt5Core.so.5
#5  0x00007fb2b31d308c in start_thread () at /usr/lib/libpthread.so.0
#6  0x00007fb2b6befe1f in clone () at /usr/lib/libc.so.6

Thread 1 (Thread 0x7fb2baaa4c80 (LWP 8015)):
[KCrash Handler]
#5  0x00007fb2b7665bf0 in QProcess::pid() const () at /usr/lib/libQt5Core.so.5
#6  0x00007fb2b8df26ea in KProcess::pid() const () at /usr/lib/libKF5CoreAddons.so.5
#7  0x00007fb290e51263 in  () at /usr/lib/qt/plugins/cantor/backends/cantor_maximabackend.so
#8  0x00007fb290e5598a in  () at /usr/lib/qt/plugins/cantor/backends/cantor_maximabackend.so
#9  0x00007fb290e50fc0 in  () at /usr/lib/qt/plugins/cantor/backends/cantor_maximabackend.so
#10 0x00007fb28c1d7cbe in  () at /usr/lib/qt/plugins/libcantorpart.so
#11 0x00007fb28c1cc33b in  () at /usr/lib/qt/plugins/libcantorpart.so
#12 0x00007fb28c21656e in  () at /usr/lib/qt/plugins/libcantorpart.so
#13 0x00007fb2b771ba06 in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib/libQt5Core.so.5
#14 0x00007fb2b845f383 in QAction::triggered(bool) () at /usr/lib/libQt5Widgets.so.5
#15 0x00007fb2b8461c06 in QAction::activate(QAction::ActionEvent) () at /usr/lib/libQt5Widgets.so.5
#16 0x00007fb2b855cc1c in  () at /usr/lib/libQt5Widgets.so.5
#17 0x00007fb2b855ce8e in QAbstractButton::mouseReleaseEvent(QMouseEvent*) () at /usr/lib/libQt5Widgets.so.5
#18 0x00007fb2b8642ddb in QToolButton::mouseReleaseEvent(QMouseEvent*) () at /usr/lib/libQt5Widgets.so.5
#19 0x00007fb2b84a5e38 in QWidget::event(QEvent*) () at /usr/lib/libQt5Widgets.so.5
#20 0x00007fb2b8642e75 in QToolButton::event(QEvent*) () at /usr/lib/libQt5Widgets.so.5
#21 0x00007fb2b8465e3c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#22 0x00007fb2b846dd91 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#23 0x00007fb2b76eb1e0 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/libQt5Core.so.5
#24 0x00007fb2b846cd1a in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool) () at /usr/lib/libQt5Widgets.so.5
#25 0x00007fb2b84c1289 in  () at /usr/lib/libQt5Widgets.so.5
#26 0x00007fb2b84c39a0 in  () at /usr/lib/libQt5Widgets.so.5
#27 0x00007fb2b8465e3c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#28 0x00007fb2b846d816 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#29 0x00007fb2b76eb1e0 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/libQt5Core.so.5
#30 0x00007fb2b7c5c634 in QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) () at /usr/lib/libQt5Gui.so.5
#31 0x00007fb2b7c5e186 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () at /usr/lib/libQt5Gui.so.5
#32 0x00007fb2b7c35bbc in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Gui.so.5
#33 0x00007fb2ab22928d in  () at /usr/lib/libQt5XcbQpa.so.5
#34 0x00007fb2b76e982b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#35 0x00007fb2b76f2b18 in QCoreApplication::exec() () at /usr/lib/libQt5Core.so.5
#36 0x000055c8edd4f86c in  ()
#37 0x00007fb2b6b1af4a in __libc_start_main () at /usr/lib/libc.so.6
#38 0x000055c8edd4ffca in _start ()
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extra/cantor 17.12.1-1 (kde-applications kdeedu)
    KDE Frontend to Mathematical Software

community/julia 2:0.6.2-1
    High-level, high-performance, dynamic programming languageextra

kalgebra 17.12.1-1 (kde-applications kdeedu)
    Graph Calculator

community/luajit 2.0.5-1
    Just-in-time compiler and drop-in replacement for Lua 5.1

community/maxima-ecl 5.41.0-1
    A sophisticated computer algebra system (compiled against ecl)

community/octave 4.2.1-8
    A high-level language, primarily intended for numerical computations.

extra/python2 2.7.14-1
    A high-level scripting language

extra/python 3.6.4-1
    Next generation of the python high-level scripting language

extra/libqalculate 2.2.0-1
    Multi-purpose desktop calculator

extra/r 3.4.3-1
    Language and environment for statistical computing and graphics

community/sagemath 8.1-4
    Open Source Mathematics Software, free alternative to Magma, Maple, Mathematica, and Matlab

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