Predicted output time

Support
1

Hi Chris,

I saw a discussion recently in which you showed Beshoy how to predict stimulus onset to reduce jitter in timing. We’d like to use this as well- could you tell me how to do this in the XML (we’re not using MWEL).

Along these lines- could you put back some “legacy” pages for syntax for XML? Or is there a standard way to convert XML files into MWEL automatically?

Thanks,
Lindsey.

2

Hi Lindsey,

I saw a discussion recently in which you showed Beshoy how to predict stimulus onset to reduce jitter in timing. We’d like to use this as well- could you tell me how to do this in the XML (we’re not using MWEL).

The XML version of the code I shared with Beshoy looks like this:

<action type="queue_stimulus" stimulus="stim" />
<action type="update_stimulus_display" predicted_output_time="stim_onset_time" />
<action type="wait" duration="stim_onset_time - now() + 30 ms" />
<!-- Send the pulse now -->

Along these lines- could you put back some “legacy” pages for syntax for XML?

The component and expression references apply to both XML- and MWEL-based experiments. The handful of things that work only in MWEL are clearly marked as such.

The bit that might not be clear is how to use the type signature (e.g. action/update_stimulus_display for the Update Stimulus Display action) in XML. The process is

  1. The part before the slash (e.g. action) becomes the XML tag:

     <action ... />

  2. The part after the slash (if any) becomes the value of the “type” attribute:

     <... type="update_stimulus_display" ... />

All other parameters are just attributes in the XML.

Or is there a standard way to convert XML files into MWEL automatically?

I wrote a rough XML-to-MWEL converter for Mark Histed. Making a better version is on my to-do list, but I haven’t done it yet.

Cheers,
Chris

3

Great- thanks for your help!
Lindsey.