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Parameter Definition

&parameter
    STRING name = NULL
    STRING symbol = NULL
    STRING units = NULL
    STRING description = NULL
    STRING format_string = NULL
    STRING type = NULL
    STRING fixed_value = NULL
&end

This optional command defines a parameter that will appear along with the tabular data section of each data page. The name field must be supplied, as must the type field. The type must be one of short, long, float, double, character, or string, indicating the corresponding C data types. The string type refers to a NULL-terminated character string.

The optional symbol field allows specification of a symbol to represent the parameter; it may contain escape sequences, for example, to produce Greek or mathematical characters. The optional units field allows specification of the units of the parameter. The optional description field provides for an informal description of the parameter. The optional format field allows specification of the printf format string to be used to print the data (e.g., for ASCII in SDDS or other formats).

The optional fixed_value field allows specification of a constant value for a given parameter. This value will not change from data page to data page, and is not specified along with non-fixed parameters or tabular data. This feature is for convenience only; the parameter thus defined is treated like any other.

The order in which successive parameter commands appear is the order in which the parameters are assumed to come in the data. For ASCII data, each parameter that does not have a fixed_value will occupy a separate line in the input file ahead of the tabular data.

Example:

&parameter name=NUx, symbol="$gn$r$bx$n", 
  description="Horizontal Betatron Tune", type=double &end
&parameter name=NUy, symbol="$gn$r$by$n", 
  description="Vertical Betatron Tune", type=double &end
&parameter name=L, symbol=L, description="Ring Circumference", 
  type=double, fixed_value=30.6667 &end
.
.
.


next up previous contents
Next: Array Data Definition Up: Structure of the SDDS Previous: Tabular-Data Column Definition   Contents
Robert Soliday 2014-01-28