When you specify the name of the DLL file, Flexcom loads the DLL and searches for the boundary condition subroutine. Once Flexcom locates the subroutine, the subroutine is dynamically loaded into the Flexcom analysis module executable. The analysis then proceeds. When running, the user-subroutine is called once at each solution time for each node and DOF you specified as having an arbitrary boundary condition applied. The subroutine arguments contain sufficient information for you to be able to determine which combination the subroutine is being called for (presuming there is more than one), and you must program your module accordingly, typically using statements such as “if”, “then”, “else” etc. Finally, when the analysis is completed the temporary Flexcom executable is deleted. Note that if you invoke this user-subroutine facility, then the operation is completely automatic and transparent to you, and requires no intervention by you at runtime in compiling or linking the program.
