- type: action/setup command.
- function: load data from SDDS file into RPN variables.
- Command syntax, including use of equations and subcommands, is discussed in 7.2.
STRING tag = NULL;
STRING filename = NULL;
STRING match_column = NULL;
STRING match_column_value = NULL;
long matching_row_number = -1;
STRING match_parameter = NULL;
STRING match_parameter_value = NULL;
long use_row = -1;
long use_page = -1;
long load_parameters = 0;
This command is used to facilitate multi-stage optimization runs by allowing convenient loading of
data from SDDS files into RPN variables. For example, one may match the final Twiss parameters of a
lattice to the parameters stored in an SDDS file from a different run.
- tag — Option string that will be pre-pended to the names of all the numerical columns in the
file in order to create RPN variable names. E.g., if the input file was from the twiss_output
command and tag = tw1 was given, then RPN variables tw1.betax, tw1.alphax, etc. would
be used. N.B.: If the tag is blank, then nothing is appended to the names from the file. This
can be dangerous since the names may conflict with the names of other variables!
- filename — The (incomplete) name of the SDDS file from which to read data. By default, data is
taken from all columns from the last row of the last page of the file. This default behavior can be
altered using one or more of the following parameters:
- match_column — The name of a string column to use in selecting the row from which
data will be taken.
- match_column_value — The value that the column named by match_column must have
to be selected from the file. By default, the last row with a matching value is used.
- matching_row_number — If a nonnegative value is given, then the
matching_row_numberth matching row is selected (0 is the first row, 1 the second, etc).
Otherwise, the last match row is used. Ignored if match_column is not given.
- match_parameter — The name of a string parameter to use in selecting the page from
which data will be taken.
- match_parameter_value — The value that the parameter named by match_parameter
must have to be selected from the file. By default, the last page with a matching value
- use_row — If nonnegative, specifies the row number to use, starting at 0 for the first
row. Ignored if match_column is given.
- use_page — If nonnegative, specifies the page number to use, starting at 1 for the first
page. Takes precedence over \match_parameter if both are given.
- load_parameters — If nonzero, specifies loading the SDDS parameter data rather than
the column data.