itsme

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12 years, 328 days

MaplePrimes Activity


These are replies submitted by itsme

thanks for posting this!... very nice, and could be very useful.

@Kitonum 

did you submit this? certainly seems like inconsistent behavior

@Carl Love 

Thanks Carl - somehow didn't come across this before... 

@ecterrab 

 

just a word of caution... in some cases one will get a wrong (unexpected?) result. For example, consider

with(Physics):
Setup(operator = {A})

f:=exp(A(t));

diff(f,t); #wrong answer in general - assumes [A(t), diff(A(t),t)]=0, but does not have to be true.

it's easy to see that this is also in general wrong:

restart:

with(Physics):
Setup(operator = {A, B})

f:=exp(A(t) + B(t));

diff(f,t);  #wrong

Thanks for looking into this in detail @epostma 

As a side note...  It would be nice to make the source code of maple modules browsable, as that would make it easier for users to understand what it is that they actually doing/using. 

 

thanks for taking the time to post this info @epostma !

It helps very much indeed!... it could also be a good idea to mention this information in the help section. 

 

 

bump...

mr/ms maple developer - i'm sure you're out there...  ;)

@acer 

thanks Acer. Hopefully the devs can shed some light on this. 

@Mac Dude 

you can run vnc over ssh.

also... nomachine nxserver/client... again runs over ssh. 

@Prashanth 

regarding the maplet issue - i have not used maplets other than trying simple things in the past which lead to problems. It could be settings related but I doubt that, if you're seeing a problem with the simplest of plots. Submitting SCRs is alwas a good idea. 

However, more generally, trying to plot from the command line to a file is pretty broken as well. Some plots work (as in a curve is visible), but if you want any customization (font size change, etc) you'll likely have issues. Also the plots will not have things like antialiasing and are ok, for say a quick look, but IMO are not really presentable. 

Your milage may vary in all of this... so you might still want to try things out for yourself. I spent a lot of time trying to get things to work, as I had aceess to a gui-less many cpu-cluster, and watned to generate many plots in a batch mode - it was a rather painful experience, and i eventually gave up.

@Prashanth 

i see. You're probably out of luck then, the plotting from the command line has been neglected for years. 

Again, depending on what kind of "interactive features" you need, some other packages might be useful - matplotlib (with a toolkit) allows for interactive rotation/zoom in 3d plots. 

alternativey, since you're writing in java, another option could be to generate your data using maple, then plot using a native java library. 

if its a simple x vs f(x) plot, your best option is to simply save to a file (say myplot.png), then open the file in a program that autoupdates on change - this will always give you the latest plot that is generated. 

if you have more complicated plots (and cannot use a gui), then your best option is to export the data from maple and simply plot the data to a file via a separate program (you can write very simple code using matplotlib, or even use gnuplot or equivalent). This is painful because its a two-stage process, but you can automate it by using maple's "system" or "ssystem" calls...

 EDIT

looking at your last screenshot, i should note that of course the best way forward is to know more about what you need to do. For example, instead of calling every command separately from java, it might easier to simply create a maple script (i.e. a text file with a .mpl extension) and call that. One can easily pass variables to such a script using the -c flag. See this post for an example:

 

 

http://www.mapleprimes.com/questions/145579-Can-I-Write-A-Shell-Script-That-Executes#answer145727

 

 

@mthkvv 

 

I have two Intel Xeon E5504 2.00 GHz - 8 cores/threads in all. And 8 nodes - most efficient mode on my machine in other cases.

yup, makes sense in your case then to use 8.

@mthkvv 

 

(I've tried with numnodes=4 - worked normally. But I need full options - 8 nodes and may be more.)

i tried with 4 as well.

on my cpu, maple defaults to 4 nodes. My cpu has 4 cores, but the OS sees it as 8 because of intels hyperthreading... note however that in all the problems i have looked at, forcing maple to use 8 numnodes has resulted in degraded performace (i would expect this - cpu cache, all memory access infrastrucutre, is shared between two hyperthreads on a single core). This behavior is very problem-dependent, but for my tasks, I have found the optimal number of nodes to be 4-5... not more.

What CPU do you have?... unless you really have an 8 core machine (not 4 core / 8 thread one), setting numnodes to a higher number might not be helpful.

 

 i have set the java heap that maple uses to 2048 MB in the startap maple script

How you did this? Edit launch.ini ?

on linux you can modify the /usr/bin/maple script (at your own risk!). i don't know how this is done in windows.

@mthkvv 

both the threaded as well as grid calls that you have showed (but with colons at the ends) seem to complete on my machine, without crashing...

i am on linux x86_64... also, i have set the java heap that maple uses to 2048 MB in the startap maple script, but since we don't really know how Grid works behind the scnens it's hard to say if that is what is actually helping - either way you might try it.

other than that, an SCR might be your best bet, as Alejandro points out.

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