Maxima on android hangs with plot2d



Hi Richard Fateman and Yasuaki Honda,

I answer Richard's comments in his text.
I have then tried a little experimentation using ssh to get some 
information on running processes in android. Maybe it will be helpful, I 
don't know.

Le 10/09/13 16:33, Richard Fateman a ?crit :
> Hi Eddy F ( and Yasuaki Honda):
>
> I find (on Windows...) that the default settings for plotting allows
> only one plot at a time.
> To resume Maxima, you must kill the (gnuplot) window by clicking on the
> [X].

Unfortunately, I've got no way to kill the gnuplot window on android. No 
cross to click on, no gnuplot item in the activ app list. When the plot 
window is displayed, the android menu icon is visible (it normally is 
not if there is no menu) but this icon doesn't do anything. That, in 
itself, I find rather strange.

> Maybe the
> same kind of thing is happening on Android -- you have a plot process
> that is taking
> precedence over the Maxima main window and taking all input.

Yes, that explanation is quite plausible indeed.

Just a little precision: maxima doesn't hang after the first plot but 
after trying to plot again. If after the first plot I enter a simple 
command like 7*8; maxima responds. It is only another plot command that 
makes it hang.

>
> I think there are other settings that allow multiple plots(on windows),
> so maybe your default setting is
> not right.
>
>
> RJF

No. Unfortunately, Maxima for Android provides almost no setting option 
(except one to chose the language of the manual).

A little experiment:

I completely shutdown my device.
I start it.
I start a ssh connection from my laptop to this tablet. I will use the 
ps command in this ssh session.
First ssh command, before maxima is started gives no entry related to 
maxima (of course).

I start maxima.
The ps command gives those two lines
app_111   2832  99    514492 58344 ffffffff 00000000 S jp.yhonda
app_111   2856  2832  37496  22140 ffffffff 00000000 R 
/data/data/jp.yhonda/files/maxima

I enter a simple command in maxima, says 7*8;
The ps command now gives
app_111   2832  99    514832 59252 ffffffff 00000000 S jp.yhonda
app_111   2856  2832  45752  31852 ffffffff 00000000 S 
/data/data/jp.yhonda/files/maxima

I enter a simple plot2d command, while the plot is still being 
displayed, the ps command gives
app_111   2832  99    518564 62072 ffffffff 00000000 S jp.yhonda
app_111   2856  2832  45752  32124 ffffffff 00000000 S 
/data/data/jp.yhonda/files/maxima

While the plot is displayed, the android menu icon is displayed but is 
inactive. The only way for me to make this plot disappear is to use the 
back icon. The ps command then gives
app_111   2832  99    519524 62300 ffffffff 00000000 S jp.yhonda
app_111   2856  2832  45752  32124 ffffffff 00000000 S 
/data/data/jp.yhonda/files/maxima

I enter another simple command. Maxima responds and the ps command says
app_111   2832  99    519600 62524 ffffffff 00000000 S jp.yhonda
app_111   2856  2832  45752  32124 ffffffff 00000000 S 
/data/data/jp.yhonda/files/maxima


I try another plot2d command. Maxima hangs. The ps command now gives 3 
lines :
app_111   2832  99    519672 62800 ffffffff 00000000 S jp.yhonda
app_111   2856  2832  45752  32124 ffffffff 00000000 S 
/data/data/jp.yhonda/files/maxima
app_111   3020  2832  511068 44516 ffffffff 00000000 S jp.yhonda


Could this 3rd line give any indication about what is going on ?

I "kill" maxima in the android "task manager" but after that the ps 
command still gives those two lines
app_111   2856  1     45752  27364 ffffffff 00000000 S 
/data/data/jp.yhonda/files/maxima
app_111   3020  1     511068 41380 ffffffff 00000000 S jp.yhonda

Could this process with pid 3020 that appeared after first plot be 
responsible for maxima hanging ?
If I could find a way to kill this process and see if maxima still 
hangs... Alas, to my knowledge, android doesn't provide a way to do 
that. I am going to look in the android market (or whatever google 
choses to call it today) if I can find a way to kill a specific process. 
In that case, maybe I would find a way to provide further information. 
Alas this device is not rooted and I am not allowed to do it (I do not 
own the device).

Thanks for reading.

-- 
Eddy F.