Conceptual structure of an ndata file
The file consists of a header and a set of trials.
headerThe header contains the following information:
- class - a string describing the nature of the data file.
- constant parameters - names, values, and types (i-integer, f-float, or c-char) for parameters that remain constant for the data file.
- variable parameters - names and types (i, f, or c) of parameters whose values changes across trials in the data file.
- event code tables - each table contains a list of code numbers and their meaning.
- number of trials - the number of data trials in the file.
trialA trial consists of a trial header and a list of records.
- trial code - usage varies.
- time reference - A global time reference, if one is available, for the start of the trial.
- variable parameters - names and values for this trial. Types must match those in the file header.
- nrec - number of records in this trial.
- record type - one of the following values
- 0 - point integer (e.g., a list of spike times)
- 1 - float (e.g., membrane voltages)
- 2 - point-value (e.g., integer time and float value)
- 3 - event code (e.g., a list of event codes at integer times)
- record name - a name describing the record (e.g., unit0), which associates this record with similarly named records in other trials. A collection of records having the same name is called a channel.
- sampling - samples per second (e.g., 1000.0 for milliseconds)
- t0 - time origin of record data relative to the trial time reference.
- tn - time duration of the data (in sampling unints)
- n - number of data points.
- record data - the stored data depends on the record type.