parameter - SpecTcl Command
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parameter - SpecTcl Command |
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SpecTcl Home General Information User Guide Programmer's Guide Obtaining and Installing
parameter [-new] name id resolution
parameter [-new] name id resolution {low high units}
parameter [-new] name id [units]
parameter -list [-byid]
parameter -list [pattern]
parameter -list -id id
parameter -delete name
parameter -delete -id id
Manipulates the SpecTcl parameter dictionary.
SpecTcl maintains a parameter dictionary. The parameter dictionary creates a correspondence between elements in the Event dynamic array and named parameters which are used to create spectra. Each parameter has the following properties:
While the internal representation of a parameter is a floating point value, SpecTcl recognizes that many parameters are integer values (e.g. raw ADC conversions). SpecTcl provides a rich set of parameter range definitions that cover the span of both real and integer valued parameters.
The spectrum command is used to create spectra which histogram parameters.
Creates a new entry in the parameter dictionary. The -new flag is optional. This comand has several forms, depending on whether the parameter is to be treated as an integer, a mapped integer or a real number. All parameters have a name and an Id. The name is an arbitrary text string (although since you are working within Tcl, using {}[] e.g. in parameter names is strongly discouraged).
The name is the name you will use in future SpecTcl commands to refer to this parameter. The id represents the slot in the parameter array in which your unpacking software will place the parameter.
An integer parameter is assumed to have a value from 0 to (2**n)-1. n is said to be the scale of the parameter. Two types of integer parameter may be defined, depending on the form of the parameter command:
parameter [-new] name id scale
Defines an integer parameter whose values represent the range [0,(2**scale) - 1].
parameter [-new] name id scale {low high units}
Defines a parameter with range defined as in the first form of the command, but whose values are assumed to linearly map to some real coordinate line in the range [low,high]. The command parameter low and high are floating point values. The parameter is also assumed to have units (e.g. cm or MeV) described by the string unit. Parameter of this sort are called mapped parameters and are useful when building histograms of simple calibrated parameters.
A real parameter has an arbitrary range, and optional units. It is defined as follows:
parameter [new] name id [units]
The units parameter is a string valued command line parameter that represents the units of the parameter (e.g. "MeV").
Returns a list of the parameter definitions. If the optional -byid switch is included, the parameters are sorted by Id number. Otherwise the list is alphabetical by parameter name. The output is in a form which makes processing by other Tcl commands and scripts easy (see e.g. ParList). The output is a Tcl List of definitions. Each element of the list is itself a list that describes one parameter. In order to make the processing of this list simple, all parameter definitions have the following elements (in order):
| Element | Meaning | ||||||||
| name | Name of the parameter | ||||||||
| id | Index into the parameter array of the parameter. | ||||||||
| scale | Scale value of the parameter if it is an integer valued parameter else empty. | ||||||||
| info | This is a three element list containing in order
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Sample output:
{Distribution1 1 10 {{} {} {}}}
{hasunits 12 {} {{} {} {cm}}}
{real 7 {} {{} {} {}}}
{scaled 6 10 {10.000000 20.000000 MeV}}
This sample shows in order the output for a simple integer parameter, a real parameter with units, a real parameter with no units and a scaled integer parameter.
Returns a parameter list of whose whose name matches the pattern. The pattern may include * as a wildcard. The -byid falg is optional and will cause the parameters to be sorted by id number instead of by name.
Returns the parameter definition for the parameter with the id id. If the parameter cannot be listed, the return value is an error message string.
Removes the parameter named name from the parameter dictionary.
Removes the parameter with the id id from the parameter dictionary.
parameter De1 0 12 ;# Creates a 12 bit parameter named De1 in element
# zero of the event array.
parameter p1 1 10 {10 100 "MeV"} ;# Creates a 10 bit parameter named p1 which will
# scale channel data to between 10 and 100, and
# will label its axis with "MeV".
parameter position 2 mm ;# Defines a real valued parameter with units mm
parameter -list -byid ;# Creates a list sorted by Id of the defined
# parameters.
parameter -delete -id 0 ;# Deletes the parameter with the id 0.
ParList [parameter -list -byid] ;# Uses the ParList script to create a nicely
# formatted list of parameters sorted by ID.
SaveParams setup.tcl [parameter -list] ;# Uses the Saveparams script to create a file
# called setup.tcl which contains definitions
# for all of the parameters known to SpecTcl.
# This script can then be sourced to re-define
# these parameters on subsequent runs.
SpecTcl Home General Information User Guide Programmer's Guide Obtaining and Installing
Last Modified: October 28, 2003 by: fox@nscl.msu.edu
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