Parameters in SpecTcl

SpecTcl user code is responsible for unpacking events into a flat array of parameters.   The user of SpecTcl supplies information about each element of the array which is of interest.  An element of an event array is called a Parameter.  There are two types of parameters:

• Raw parameters, created by the SpecTcl user code.  Note that significant computing may be required in the user code to produce a raw parameter, but as far as SpecTcl is concerned, any parameter produced by the user's code is a raw parameter. 
• Pseudo parameters, created by SpecTcl scripts via the pseudo command.  These are pseudo parameters which can be created on the fly as bits of Tcl code.

All parameters have a name, a resolution,  as well as an Id.  Additionally, a parameter can contain information for performing arbitrary coordinate mapping of the spectrum coordinates. This information would consist of a lower and upper value for scaling a mapped spectra, and an axis label. A parameter's ID is just the index (from 0) into the parameter array at which it is stored.  The parameter name is used to refer to the parameter when creating spectra, gates or pseudo parameters.  The parameter resolution is the number of bits of resolution of the parameter.  It is used, in conjunction with the spectrum resolution, to scale the parameter when incrementing spectra.

For complex experiments, the concept of a flat parameter space may be insufficient.  Daniel Bazin has produced parameter classes which support a more structured parameter space.  Contact bazin@nscl.msu.edu

Last Modified: October 28, 2003 by: fox@nscl.msu.edu
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