Name	if_endif

Author: John Tee
        Consultant
        Advanced Visual Systems, Inc.
        Staines, UK

Module Sources:  if_f.f
                 endif_f.f

Inputs: Field

Outputs: Field

Parameters:
         Flag    (boolean)

Language: FORTRAN

Description:
    Two modules, "if" and "endif" can be used to make a logical
    branch in a flow network. The "if" module copies the input
    to one of two output ports, based on a boolean flag, while
    "endif" copies one of two input ports data to the output port,
    closing the condition. Different processing modules can then
    be placed along the two logical branches of the network.
    Both modules are in Fortran, and dynamically allocate new
    space for the output fields.