next up previous contents
Next: Parameter Definition Up: Structure of the SDDS Previous: Data Set Description   Contents

Tabular-Data Column Definition

&column
    STRING name = NULL
    STRING symbol = NULL
    STRING units = NULL
    STRING description = NULL
    STRING format_string = NULL
    STRING type = NULL
    long field_length = 0
&end

This optional command defines a column that will appear in 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 column; it may contain escape sequences, for example, to produce Greek or mathematical characters. The optional units field allows specification of the units of the column. The optional description field provides for an informal description of the column, that may be used as a plot label, for example. 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).

For ASCII data, the optional field_length field specifies the number of characters occupied by the data for the column. If zero, the data is assumed to be bounded by whitespace characters. If negative, the absolute value is taken as the field length, but leading and trailing whitespace characters will be deleted from string data. This feature permits reading fixed-field-length FORTRAN output without modification of the data to include separators.

The order in which successive column commands appear is the order in which the columns are assumed to come in each row of the tabular data.

Example (using sddsplot conventions for Greek and subscript operations):

&column name=element, type=string, description="element name" &end
&column 
    name=z, symbol=z, units=m, type=double, 
    description="Longitudinal Position" &end
&column 
    name=alphax, symbol="$ga$r$bx$n", units=m, 
    type=double, description="Horizontal Alpha Function" &end
&column 
    name=betax, symbol="$gb$r$bx$n", units=m, 
    type=double, description="Horizontal Beta Function" &end
&column 
    name=etax, symbol="$gc$r$bx$n", units=m, 
    type=double, description="Horizontal Dispersion" &end
.
.
.


next up previous contents
Next: Parameter Definition Up: Structure of the SDDS Previous: Data Set Description   Contents
Robert Soliday 2014-01-28