load_parameters

• type: setup command.
• function: load parameters for elements from an SDDS file.

&load_parameters
        STRING filename = NULL;
        long change_defined_values = 0;
        long clear_settings = 0;
        long allow_missing_elements = 0;
        long verbose = 0;
&end

• filename -- Name of SDDS file from which to take data. The file must contain some of the following columns:
  • ElementName -- Required string column. The name of the element to change.
  • ElementParameter -- Required string column. The name of the parameter of the element to change.
  • ParameterValue -- Optional double column. If given, gives value of the parameter named in ElementParameter for element named in ElementName.
  • ParameterValueString -- Optional string column. If ParameterValue is not present, then this column must be present. The string data will be scanned, if necessary, to obtain a value for the parameter.
  • ParameterMode -- Optional string column. If given, for each row the value must be one of ``absolute'', ``differential'', ``ignore'', or ``fractional''. The meaning of these modes is as follows: absolute mode means the given value is used as the new value for the parameter; differential mode means the given value is added to the existing value for the parameter; ignore mode means the value is ignored; fractional mode means the existing value is increased by the product of the given value and the existing value (i.e., the given value is a fractional change).
  Unless change_defined_values is set, successive pages of the file are used for successive steps of the simulation. Several elegant commands generate output that may be used (on a subsequent run) with load_parameters; among these are the tune and chromaticity correction commands and the run_setup command (parameters output).
• change_defined_values -- Changes the defined values of the parameters. This means that when the lattice is saved (using save_lattice), the parameters will have the altered values. Also, if you want to alter the values for all steps of the simulation, you must set this flag.
• clear_settings -- If set, clear all settings and files being used for loading parameters.
• allow_missing_elements -- If set, allow elements in the file that are not in the lattice. In this case, the nonapplicable data is simply ignored.
• verbose -- If set, provide informational printouts about changes to parameters.