Experiment prematurely ends after changing stimulus and window units

Coding
1

Hi, I was attempting to obtain the coordinates of one of my stimuli in centimeters. I noticed that it was in units of height. When I changed the units of the window and stimulus to cm and ran the experiment, it would prematurely end between 2-4 trials instead of running through the 5 it was programmed to do.

Originally the code read:

win = visual.Window(
    size=(Width, Height), fullscr=True, screen=0, 
    winType='pyglet', allowGUI=False, allowStencil=False,
    monitor='testMonitor', color=backgroundColor, colorSpace='rgb',
    blendMode='avg', useFBO=True, 
    units='height')

# set up handler to look after randomisation of conditions etc
trials_2 = data.TrialHandler(nReps=5, method='sequential', 
    extraInfo=expInfo, originPath=-1,
    trialList=[None],
    seed=None, name='trials_2')
thisExp.addLoop(trials_2)  # add the loop to the experiment
thisTrial_2 = trials_2.trialList[0]  # so we can initialise stimuli with some values
# abbreviate parameter names if possible (e.g. rgb = thisTrial_2.rgb)
if thisTrial_2 != None:
    for paramName in thisTrial_2:
        exec('{} = thisTrial_2[paramName]'.format(paramName))

counter = 0
randInt = random.uniform(0.1, 0.3)


for thisTrial_2 in trials_2:
    
    randInt = random.uniform(-0.2, 0.1)
        
    polygon = visual.Rect(
        win=win, name='polygon',
        width=(0.02, 0.02)[0], height=(0.02, 0.02)[1], 
        ori=0, pos=(randInt, randInt),
        lineWidth=1, lineColor=[1,1,1], lineColorSpace='rgb',
        fillColor=stimuliColor, fillColorSpace='rgb',
        opacity=1, depth=0.0, interpolate=True)

However, when I change the units of the window and stimuli like this:

# Create window
win = visual.Window(
    size=[Width,Height], fullscr=True, screen=int(settingsGui.data[3]),
    winType='pyglet', allowGUI=False, allowStencil=True, 
    monitor='testMonitor', color=backgroundColor, colorSpace='rgb',
    blendMode='avg', useFBO=True, units='cm')

for thisTrial_2 in trials_2:
    
    randInt = random.uniform(-0.2, 0.1)
        
    polygon = visual.Rect(
        win=win, name='polygon', units='cm',
        width=0.4, height=0.4,
        ori=0, pos=(randInt, randInt),
        lineWidth=1, lineColor=[1,1,1], lineColorSpace='rgb',
        fillColor=stimuliColor, fillColorSpace='rgb',
        opacity=1, depth=0.0, interpolate=True)

It does not loop through all of the trials. Is there a way to fix this? Any help would be appreciated.

2

Hi There,

are there any error messages in the stdout portion of runner view?

Thanks,
Becca

3

Hi there, sorry for the late answer. I do not get any error messages running it. Alternatively, could I just use convertToPix and then pix2cm to perform the same task? The program seems to work just fine if I do not change the units.

4

EDIT: I resolved the issue by using:

convert_pix = posToPix(polygon)
convert_cm = psychopy.tools.monitorunittools.pix2cm(convert_pix, testMonitor)
print("coordinates (cm):", convert_cm)

Which prints the converted coordinates in cm.