In some cases, an algorithm can
not be implemented with the provided operators which deal with entire tables as inputs and
outputs. A good example of this is the calculation of brittle failure factor of safety that
requires logic and control flow for each and every record that is being processed: Figure 1. Brittle Failure Factor of Safety
This type of calculation is ideally suited for an interpreter, where a user-defined
script executes for each input value. Result Math contains an operator library that allows
the user to extend it with Tcl, Templex, or even a compiled
DLL.
The Tcl procedure that performs this calculation is:
Two functions are added to the Tcl interpreter that allow access to the inputs
and a record storage interface:
GetRecordInfo – gets information about the current record.
AddRecord – stores the calculated value.
The following XML defines the input to this procedure and specifies the Tcl file
as well as what procedure to call:
The call to the “TclPlugin” operator requires the following
parameters:
src – the value table passed to the procedure.
ents – the entities that correspond to the source values (for
stress, this is elements, for displacements, it would be nodes). This allows the part id
attached to the element to be looked up with the GetRecordInfo function.
onrecord – this is the name of the procedure in the script
file.
script – path to the script file that contains the onrecord
procedure.
answer – the datatype output table.
The “TclPlugin” operator call behaves as any other built-in
operator, and is preceded or followed by calls to other operators to leverage the speed of
table-based operators along with the flexibility of calling user-defined scripts. The output
for this example is: Figure 2.
