9 Commands

This chapter lists all the commands available to IFEFFIT. As discussed in section 3.6, the basic syntax for IFEFFIT commands is

 Iff> command(key = value, key = value, key = value, ... )

That is, each command recognizes a set of command arguments, usually given as keyword/value pairs, where the keyword itself determines what type of variable will be read from the value field, and what the command will do with that value. Some commands also use simple lists (comma delimited, but without the form key = value) for some or all of their input arguments.

Some commands read default values for their command parameters from the global set of Program Variables. Such default values are always read before the keyword/value arguments are read, so that explicitly using the corresponding argument will always overwrite the default value. Many commands will write or change output values (scalars, arrays, and/or strings) to the global set of Program Variables.

For each command, the following sections will list these attributes:

Description

gives a brief description of the command. This description does not include much information about the algorithm used or when the use of the command would be appropriate for EXAFS analysis.

Input Program Variables

lists the Program Variables read as the default values of the command parameters.

Keywords/Values

describes the keywords for the command parameters, usually with a table of keywords, default program variable used for input, default value (if not given and default program variable is not set), and a description of the parameter (Keyword, Variable, Default, and Description respectively). Many commands have default keywords for the first few keywords - these are indicated by a leading superscript: ¹file would mean that file was the default for the first keyword.

Output Program Variables

lists and describes the program variables that are created or modified. When arrays are created, they are listed with the generic group name $GROUP, which will be substituted by the current value of $group.

Notes

gives some additional information on the command, typically pointing out the unusual program variables used.

Examples

lists one or more examples of this command, though not necessarily using every feature.

See also

lists similar commands and other places in this Reference Guide

Many of the IFEFFIT commands use similar syntax, program variables, and conventions for their command arguments. This is especially true for the input and output of scalars and data arrays, and for parameters used in background removal and Fourier transforms. To this end, and for the sake of brevity and coherence, the glossary in Appendix A contains more detailed description of the common program variables and conventions used. Additional hints can usually be found in the Notes: section.