The COMPLEX function returns complex scalars or arrays given one or two scalars or arrays. If only one parameter is supplied, the imaginary part of the result is zero, otherwise it is set to the value of the Imaginary parameter. Parameters are first converted to single-precision floating-point. If either or both of the parameters are arrays, the result is an array, following the same rules as standard IDL operators. If three parameters are supplied, COMPLEX extracts fields of data from Expression .
Offset from beginning of the Expression data area. Specifying this argument allows fields of data extracted from Expression to be treated as complex data. See the description in Constants and Variables for details.
When extracting fields of data, the D i arguments specify the dimensions of the result. The dimension parameters can be any scalar expression. Up to eight dimensions can be specified. If no dimension arguments are given, the result is taken to be scalar.
When converting from a string argument, it is possible that the string does not contain a valid floating-point value and no conversion is possible. The default action in such cases is to print a warning message and return 0. The ON_IOERROR procedure can be used to establish a statement to be jumped to in case of such errors.