====== Pattern files ======

''pat'' - or pattern files are used in Auryn to defined patterns as a subset of neurons of single [[NeuronGroup]] with associated activity (gamma) value between zero and one. They are a human readable exchange format and are understood by a range of Auryn objects. [[SparseConnection]] for instance implements a set of functions to load such pattern files as cell assemblies (or synfire chains) into the connection matrix. [[PatternMonitor]] on the other hand allows to record firing rates from neural subpopulations specified by ''pat'' files and finally [[WeightMonitor]] has a set of functions to monitor synaptic weights within or between neurons specified in a ''pat'' file.

===== File structure =====

The first bit of a ''pat'' file could look like this:
<code>
# 2 blocks
# pattern 0
0 0.866623
1 0.742221
2 0.271302
398 0.208315 
399 0.123721 
 
 
# pattern 1 
400 0.972103 
401 0.057406 
</code>
where the first column specifies the [[NeuronID]] and the second column the associated gamma value. Different patterns in a single pattern file are **separated by 2 or more line breaks**. Comments can be added to the file and have to be marked with a leading ''#'', which has to be the first character on a line. If the second column is missing the value will be interpreted as 1.0. Therefore a pattern file without second column is also a valid pattern file. 

==== See also ====
[[PatternMonitor]] and [[StimulusGroup]].