[visionegg] pre-loading a large number of stimuli

Hi everybody,

(note: this will probably be the beginning of a large barrage of questions as I try and implement a standard blocked design fMRI experiment in VisionEgg)

I'm trying to pre-load a large number of stimuli for an experiment; say, on the order of up to 400 or so. My loop to load the stimuli is the following (taken out of context):

stimuli = []
for condition in filelist:
texture_list = [Texture(filename) for filename in condition]
stimuli.append([TextureStimulus(anchor = 'center', position = (round(position[0]), round(position[1])), texture = texture, size = texture.size, texture_min_filter = gl.GL_LINEAR) for texture in texture_list])

(filelist is a list of images to load, indexed first by condition, next by image; in this case, it's a list of dimensions 4 by 80)

It seems to bomb out at around 200 images, however, giving the following error:

2005-08-15 20:13:16,390 (7856) CRITICAL: Traceback (most recent call last):
File "test_rsvp.py", line 65, in ?
File "/Users/nknouf/Development/VisionEgg_work/nklab/experiments/ common.py", line 67, in createTexturesFromFilelist
File "/Users/Shared/Library/Python/2.3/lib/python2.3/site-packages/ VisionEgg/Textures.py", line 171, in __init__
File "/Users/Shared/Library/Python/2.3/lib/python2.3/site-packages/ PIL/Image.py", line 1717, in open
IOError: [Errno 24] Too many open files: '2 objects/gun 25.tif'

Looking at the source for PIL.Image, it appears to be running into the per-user open-file limit (since it runs the standard-library "open") command. I know that PILs open command only creates a file- handle, and actual reading of the data is deferred until later.

Is there a way to force PIL, through VisionEgg, to read the file when creating a Texture() object, such that I don't exceed the open file limit? I know I could simply increase the limit, but I'd rather not do that.

Thanks,

nick knouf
lab manager, kanwisher lab

PS BTW, is there a reason why all of the demos use " texture_min_filter = gl.GL_LINEAR" as a keyword argument to TextureStimulus, especially since the help information says that texture_min_filter already defaults to gl.GL_LINEAR?
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