Simple coroutine question

mikaelr

Hello,

The coroutine function is fantastic, but I'm not able to get the coroutine to end after a button press. Basically I present a stimulus for 500ms, it is replaced by a blank screen for up to 1500ms (before a 2000ms timeout - and this is where the coroutine function came in handy). But I've tried setting the duration of the coroutine to 'keypress' and it doesn't seem to work - am I missing something very obvious?

Thank you!

sebastiaan

Hi,

That's an interesting question. Right now, coroutines has a fixed duration. But what you could do is define your own generator function in an inline_script that

1. Checks whether a response has been given; and if so
2. Changes the coroutines duration to 0, triggering an immediate timeout.

Like so:

def break_coroutines():

    """A generator that breaks a coroutine when a response is given."""

    # To start, set response to None
    var.response = None
    yield
    # Loop while coroutines is running
    while True:
        # If a response is given, set the coroutines duration to 0, causing
        # it to stop
        if var.response is not None:
            items['my_coroutines'].var.duration = 0
            break
        # Also break if the coroutines signals that it's over
        keep_going = yield
        if not keep_going:
            break

You'd then add 'break_coroutines' in the 'Generator function name' field of the coroutines plug-in.

It's a bit of a hack though ... I'll see if I can think of a more elegant way to do this.

Cheers,
Sebastiaan

mikaelr

Hi Sebastiaan,

Great thank you! I will give it a shot and let you know how it goes.

Best,
Mikael

mikaelr

Hi Sebastiaan,

So I am getting a 'zero division error' - float division by zero. It seems like the loop in the inline script isn't working: if I set items['my_coroutines'].var.duration = 1 then I see subsequent trials for 1ms, so the script is not only applying the 'set coroutines duration to 0' to a single trial, but to every subsequent trial.

sebastiaan

Ow right! You need to set duration back to its original value before the coroutines is started. To do so, you can add an inline_script immediately before the coroutines plug-in, with the following code in it (either in the Run or Prepare phase):

# Replace 5000 by the original duration of the coroutines
items['my_coroutines'].var.duration = 5000

mikaelr

Works great! I placed it in the prepare phase of the main script you passed along - a super useful fix!