vary_element

• type: setup command.
• function: define an index and/or tie a parameter of an element to it.

&vary_element
    long index_number = 0;
    long index_limit = 0;
    STRING name = NULL;
    STRING item = NULL;
    double initial = 0;
    double final = 0;
    long differential = 0;
    long multiplicative = 0;
    long geometric = 0;
    STRING enumeration_file = NULL;
    STRING enumeration_column = NULL;
&end

• 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.