
  build_variables - Builds the BDD variables necessary to compile the model
  into BDD.
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   build_variables [-h] [-i order-file]
   
   Generates the boolean BDD variables and ADD needed to encode
   propositionally the (symbolic) variables declared in the model.
   The variables are created as default in the order in which they appear
   in a depth first traversal of the hierarchy.
   
   The input order file can be partial and can contain variables not
   declared in the model. Variables not declared in the model are simply
   discarded. The variables declared in the model not listed in the input
   file are created at the end of the given ordering following the
   default ordering.
   
   Command options:
   
   -i order-file
          Sets the environment variable input_order_file to order-file,
          and reads the variable ordering to be used from file
          order-file. This can be combined with the write_order command.
          The variable ordering is written to a file, which can be
          inspected and reordered by the user, and then read back in.
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   Last updated on 990119 20h08
