7.75 vary_element

• type: setup command.
• function: define an index and/or tie a parameter of an element to it.
• sequence: must follow run_control
• N.B.: It is not possible to vary an element if the element name starts with one of the following characters: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, ., +, or -. The reason is that elegant will attempt to make an SDDS parameter name containing the element name, and these characters are disallowed at the beginning of such a name.
• Command syntax, including use of equations and subcommands, is discussed in 7.2.

• index_number — A non-negative integer giving the number of the index.
• index_limit — A positive integer giving the number of values the index will take. Must be given if this index_number has not been listed in a previous vary_element command, unless enumeration_file is given.
• name — The name of an element.
• item — The parameter of the element to vary.
• initial, final — The initial and final values of the parameter.
• enumeration_file — Name of an SDDS file giving values for the item.
• enumeration_column — Column of the SDDS file giving the values.
• differential — If nonzero, the initial and final values are taken as offsets from the predefined value of the parameter.
• multiplicative — If nonzero, the initial and final values are taken as multipliers to be applied to the predefined value of the parameter in order to obtain the actual initial and final values.
• geometric — If nonzero, then variation is geometric rather than arithmetic.
• disable — If nonzero, the command is ignored.