next up previous contents
Next: Header File Include Specification Up: Structure of the SDDS Previous: Parameter Definition   Contents

Array Data Definition

&array 
    STRING name = NULL
    STRING symbol = NULL
    STRING units = NULL
    STRING description = NULL
    STRING format_string = NULL
    STRING type = NULL
    STRING group_name = NULL
    long field_length = 0
    long dimensions = 1
&end

This optional command defines an array 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 array; it may contain escape sequences, for example, to produce Greek or mathematical characters. The optional units field allows specification of the units of the array. The optional description field provides for an informal description of the array. The optional format_string 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 group_name field allows specification of a string giving the name of the array group to which the array belongs; such strings may be defined by the user to indicate that different arrays are related (e.g., have the same dimensions, or parallel elements). The optional dimensions field gives the number of dimensions in the array.

The order in which successive array commands appear is the order in which the arrays are assumed to come in the data. For ASCII data, each array will occupy at least one line in the input file ahead of the tabular data; data for different arrays may not occupy portions of the same line. This is discussed in more detail below.

Example:

&array name=Rx, units=R-standard-units, type=double, dimensions=2,
        description="Horizontal transport matrix in standard units",
        group_name="2x2 transport matrices" &end
&array name=R-standard-units, type=string, dimensions=2, 
        description="Standard units of 2x2 transport matrices",
        group_name="2x2 transport matrices" &end
&array name=P, units=P-standard-units, type=double, dimensions=1, 
        description="Particle coordinate vector in standard units" &end
&array name=P-standard-units, type=string, dimensions=1, 
        description="Standard units of particle coordinate vectors" &end
.
.
.


next up previous contents
Next: Header File Include Specification Up: Structure of the SDDS Previous: Parameter Definition   Contents
Robert Soliday 2014-01-28