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== General ==
{{see also|Presentation}}
Presentation (www.neurobs.com) is a MS Windows based programming tool that allows experimenters to set up and program all sort of experiments. It is the recommended software for time-accurate experiments and therefore supported by the institutes’ (Social Sciences Faculty, the MPI and the Donders Centre for Cognitive Neuroimaging) technical groups.
This page documents some bugs we encountered in Presentation. Users should go to the [[Presentation]] page.
The technical groups offer (PhD) students a couple of preprogrammed experiments (i.e. templates), which can be adjusted to build up own experiments. In this way, the (PhD) student can efficiently program experiments fitting an technical optimal environment.
This is what this course is all about. It aims at teaching programming skills, which are needed to modify the existing templates such that they meet your own demands. Because this can be quite complex, we start with short assignments, which address one basic and simple problem at a time. They will all contribute to the final assignment in which you will work on an existing template.
== Software ==
Please install this version on your computer:
32-bit: [[Media:Presd171031514.zip]]


64-bit: [[Media:Presd171031514_64.zip]]
== Screen synchronization issue on 120 Hz screens ==
There is a serious synchronization issue where the picture.present() method returns one frame too early. It can be detected by measuring the time between two consecutive present() calls returning:


== License ==
<pre>
To run presentation in the labs you need a software dongle. Reserve a dongle when you book a lab. If you need a dongle for research outside the university you could discuss time limits with Ronny Janssen.
wait_interval(220);
picture1.present();
int t0 = clock.time();
picture2.present();
int t1 = clock.time();
int dt = t1-t0;
</pre>


When you want to run in in your office use the network license.
One would expect ''picture1'' to be shown for 1 frame (1/120 s) and time ''dt'' to show this. Sometimes this is not the case. The image will be shown for one frame (1/120 s), but ''dt'' will be 2/120 s:
Boot presentation, choose option "activations" -> "Network" fill in the following:
Network License Settings: Enable
IP Address: 131.174.202.11
Port: 1245
Timeout (ms): 5000
[[File:PresentationLicentie.jpg]]
== Course ==
Find the presentation workshop documentation here [[Media:Programming with Presentation_2013.pdf]]


Find the presentation prereader here [[Media:presentation pcl pre-read_2013_.pdf]]
[[File:Timeline.svg|400px|none|synchronization bug timeline]]


== Template ==
The fact that ''picture1'' is shown for only 1/120 s was confirmed with a light sensor connected to an oscilloscope.
Find the presentation Template here [[Media:Template2014.zip]]


== Other Templates ==
The chance of this issue occurring is highly dependent on the waiting time prior to the first ''present()'' call:
 
[[File:Occurrence.png|400px|none|synchronization bug occurrence]]
 
Neurobs people seem to [http://www.neurobs.com/menu_support/menu_forums/view_thread?id=9463&expand_all=1 think] it has something to do with triple buffering, but the graph above was created without triple buffering enabled.
[[File:Failsync2.png|none|Difference of arrival times of two consecutive markers (no red bars are hidden)]]
 
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