The internal matrix may be built in whole or in part (see Updates below) by reading data from an input ASCII data file (for which the default extension is .dat). The input .dat file must be ‘formatted’ with a set of possible options ranging from the traditional SATURN format as described in 10.5.1 to a set of newer, more flexible, formats where, to a certain extent, the users may define their own format. The latter facility is intended to simplify the transfer of matrix data from other suites of programs such as Microsoft Excel into SATURN.
The format selection is made from the following choices:
♦ Standard SATURN-formatted input file
♦ User-defined format (with all O-D data included)
♦ Non-zero elements only with I-J indicators (one record per cell)
♦ Spreadsheet or Comma Separated (CSV) Format (one record per row)
♦ EMME/2 Format
♦ TUBA Formats 1, 2 and 3
These are defined more precisely in Sections 10.5.2 to 10.5.7 respectively and correspond closely to the “dump” formats in 10.15.
A further option allows the user to have a preliminary look at the input file prior to selecting a format option or defining sub-options.
Note that these options are part of the standard interactive matrix building procedures within MX whereby an input data file is nominated, various options are selected and subsequently an output .ufm file is created as described in 10.16. Alternatively .ufm matrices can be built from data files using the more “batch-like” procedure MXM1 as described in section 4. Note, however, that the formats of the input data files – 1) to 6) above - are the same in both cases.
We may further note that, if an “all-new” matrix is to be built interactively from data inputs (i.e., without any existing .ufm matrices being involved), then it will be necessary to initiate a run of MX using the command line:
MX I
which (see 10.1) calls $mx.exe without a (normal) initial matrix.