An External function () interfaces with other external functions written in the C language (using a native C function or, through a wrapper function, interfacing with source code written in, for example, Fortran). You can use those functions as any other functions defined in COMSOL Multiphysics. For example, use it for a user-created shared library (depending on the platform, a DLL, .so, or .dylib file).

Enter a Library path and name (the complete network path), or click Browse to locate a library to import. For each row in the table, enter a Function name (myfun, for example) and a space-separated or comma-separated list of the names of its input Arguments (x y, for example).

Enter a value in the Initialization data field. The value is sent to the library when it is loaded. Select the Thread safe check box to declare that the function is a thread-safe pure function (that is, a function that always returns the same results using the same input argument values and that does not have any side effects or output). Select this check box to improve performance.