Assorted Experience

Remember to destroy job servers after they are done. My nice animation generator crashed sometime over the weekend with the following death rattle: Traceback (most recent call last): File "animate_array_job.py", line 168, in tscale = tscale, dpi = dpi) File "animate_array_job.py", line 92, in process_file job_server = pp.Server(ppservers=ppservers) File "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/pp.py", line 336, in __init__ self.set_ncpus(ncpus) File "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/pp.py", line 494, in set_ncpus range(ncpus - len(self.__workers))]) File "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/pp.py", line 141, in __init__ self.start() File "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/pp.py", line 148, in start shell=True) File "/L...

If the jobs are too short they may not get submitted to the remote machine and may all execute on local. pp submits jobs to remote machines only after running out of workers on local File handles are opened on the remote machines. You can't pass a file handle as a function argument TypeError: can't pickle file objects

Among the many libraries for parallel processing in python I chose what seemed to have one of the simpler interfaces - Parallel Python . There is one trick that is not apparent from the docs: The function you call has to be 'self sufficient'. You basically have to write up the function you call as if it were a script. So the function has to have the imports etc within itself. This is not a biggie, but it gets confusing until you figure it out. Original code: # module x ----------------- import a import b def f1(g): f2 f3 def f2(): def f3(): # Calling script import x x.f1(2) x.f1(4) x.f1(6) x.f1(8) Parallelized code # module px ------------------------------ def pf(g) import x x.f(g) # New calling script import pp import px ppservers = () job_server = pp.Server(ppservers=ppservers) jobs = [] jobs.append(job_server.submit(px.pf, (2,)) jobs.append(job_server.submit(px.pf, (4,)) jobs.append(job_server.submit(px.pf, (6,)) jobs.append(job_server.submit(px.pf, (8,))

ls | wc -l

ax.yaxis.tick_right() Note that is you change tick properties before this (e.g. change size of labels etc.) that will be all reset

Use raise StopIteration : try: for loop: for loop: for loop: if condition: raise StopIteration() except StopIteration pass

With interactive backend (eg Tk) f = pylab.figure(figsize = (7,10)) f.get_size_inches() -> array([ 7.175, 10.175]) The saved pdf is also of this size. It becomes extreme with smaller figures: f = pylab.figure(figsize = (1,1)) f.get_size_inches() -> array([ 3.275, 1.175]) This last I can see as a function of getting the tool bar to fit. With Agg the saved figure is the size you ask for

Reading a paper about neural circuitry. Came across the word 'resonant circuitry'. Looked it up on wikipedia . Knew it had to do with band pass circuitry. Looked that up on wikipedia . Read in that entry that Thomas Pynchon claimed the character Kilroy was based on the circuit diagram for a band pass filter. You be the judge. Any hoo, went to Pynchon's page on wikipedia and started to read. On the entry for his novel V , read about yoyodyne corp. Hey I know that from the GPL. Went to the (fictional) webpage for yoyodyne cor p ... Wait. Whaa!? What's all thsi? What's the time? Where am I? What am I doing here? Wasn't I just reading a paper on neural circuitry?

So I voted as follows: KeePass Password Safe for Best Project (I would have liked matplotlib in the list) eViacam for Best New Project matplotlib for Best Project for Academia Audacity for Best Project for Multimedia (mencoder, if it was on sf, would have won mine) OpenOffice.org for Best Project for Government KeePass Password Safe for Most Likely to Change the Way You Do Everything (I would have liked matplotlib in the list) I would have liked to see Matplotlib in the categories ' Best Project' and ' Most Likely to Change the Way You Do Everything' too, but KeePass is a good choice. I didn't vote in a category when I didn't know any of the choices. eViacam is a mistake. I tried to get rid of it but couldn't cancel that vote. I picked it at first even though I knew nothing about it because I thought it was a good idea for a project, but later decided it wasn't right to vote on a project I haven't used.

nohup command 2>file1.txt 1>file2.tex & or nohup command 2>/dev/null 1>/dev/null

Put import pdb; pdb.set_trace() Where you want the code to stop. Once in debugging mode type 'r' to return from trace and be where you stopped the program. From a tip here .

Use the highest protocol you have available - which will usually be binary. So as example: import cPickle import pylab z = pylab.random((10,10)) z ndarray 10x10: 100 elems, type `float64`, 800 bytes len(cPickle.dumps(z)) -> 2371 len(cPickle.dumps(z, cPickle.HIGHEST_PROTOCOL)) -> 934 z = pylab.random((50,50)) z ndarray 50x50: 2500 elems, type `float64`, 20000 bytes len(cPickle.dumps(z)) -> 55586 len(cPickle.dumps(z, cPickle.HIGHEST_PROTOCOL)) -> 20134 For some reason, I thought the default was to use the most efficient protocol, but it isn't. cPickle.dump? Type: builtin_function_or_method Base Class: String Form: Namespace: Interactive Docstring: dump(obj, file, protocol=0) -- Write an object in pickle format to the given file. See the Pickler docstring for the meaning of optional argument proto. Hence my slow processing and bloated data files... Note that load figures out the protocol automatically...

The os module has functions ( os.rmdir, os.removedirs ) that can remove empty directories but they will not mess with non-empty ones. The shutil module has a function ( rmtree ) that will do this (From this thread in the python mailing list).

One of the frustrating things about matplotlib is its lack of 3D plotting. If matplotlib were a mediocre library it wouldn' hurt. But it is a GREAT library and produces really good looking plots. So the lack of 3D plotting sometimes makes me want to go out and strangle somebody. There has however always been a furtive 3D plotting feature in matplotlib, and apparently , its being worked on some more. Yeehah! No more futzing with pyVtk. Important links: Docs for 3D features Installing the svn code (that has all this goodness)

Drop down the 'mailing lists' tab. There is a search option there.

Use the pylab.Circle command import pylab #Imports matplotlib and a host of other useful modules cir1 = pylab.Circle((0,0), radius=0.75, fc='y') #Creates a patch that looks like a circle (fc= face color) cir2 = pylab.Circle((.5,.5), radius=0.25, alpha =.2, fc='b') #Repeat (alpha=.2 means make it very translucent) ax = pylab.axes(aspect=1) #Creates empty axes (aspect=1 means scale things so that circles look like circles) ax.add_patch(cir1) #Grab the current axes, add the patch to it ax.add_patch(cir2) #Repeat pylab.show()

I dislike the indistinct icons in the cookie manager plugin CSlite. In Firefox/extensions/{00084897-021a-4361-8423-083407a033e0}/ (the directory for this particular extension) we find chrome/cookiesafe.jar From a hint in a thread here , we learn that the .jar file is just a .zip file, and we can extract that to find skin/classic/cookiesafe and a whole bunch of .gifs there. We can then change those gifs and change the icons that are used in the application.

I was using the Permit Cookies extension for firefox, but it hasn't been updated for a few cycles of firefox updates. It works fine, but I started to look for something else. I found CS lite which has a more convenient interface (a popup menu from the status bar). The only gripe I have so far is that the icons in the status bar are not very clean.

Downloaded and started playing the Crysis demo. On my integrated graphics MoBo, naturally I had to set everything down to low, but even then it can get choppy when in the jungle. And the graphics look so crappy I think - hmm, maybe I'll just play Far Cry. Tom's hardware has a great page where you can compare the performance of various cards with various games at various settings when searching for a cheap graphics card for crysis.

And make it all mysterious and make me think like my computer has hung, until I figure out that its just the track pad.... grrrrr.... And it reset my keyboard repeat rate too...

In matplotlib, the way to change axes tick label sizes is to do: for label in ax.get_xticklabels() + ax.get_yticklabels(): label.set_fontsize(12) From matplotlib-users

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