def setOutput(self, name, outputType, filename, nSteps):
        """
        This routine sets up a mechanism for writing system information to file directly from the dynamics engine. This is equivalent to output constructed
        """
        # assert outputType in __knownOutput__, "The output type specified was not recognized."
        __knownOutputTypes__ = ['text', 'h5py', 'binary']
        assert outputType in __knownOutputTypes__, "outputType that was provided was not understood."

        for out in self.output:
            assert out.name != name, "Output class names must be unique."

        # now append the collective variable to the walker list.
        self.output.append(outputClass.outputClass(name, outputType, filename, nSteps))


    def removeOutput(self):
        """
        This routine removes the ouput pipes for information to be written to disk from the underlying dynamics engine. Right now this simply clears all existing output.
        """

        self.output = []

        return 0


walker.register(langevinWalker)

if __name__ == "__main__":
    print 'The lanegevinWalker module is a subclass of walker:', issubclass(langevinWalker, walker)

        for out in self.output:
            self.command("undump " + out.name)

        self.output = []

        return 0

    def get_time(self):
        """
        Return the time associated with the state of the walker.
        """
        return self.time

    def set_time(self, t):
        """
        Set the timestep of the walker.
        """

        self.time = t

        self.lmp.command("reset_timestep " + str(t))

        self.propagate(0, pre="yes")

        return None

walker.register(lammpsWalker)

if __name__ == "__main__":
    print 'The lammpsWalker module is a subclass of walker:', issubclass(lammpsWalker, walker)
        Returns
        ---------
        time : integer
            Returns the number of model time steps taken.
        """
        return self.time

    def set_time(self, t):
        """Set the time of the walker.

        This routine expects an integer time in the number of model timesteps.

        Parameters
        -----------
        t : integer
            An integer specifying the number of model timesteps taken.
        """

        self.time = t

        self.lmp.command("reset_timestep " + str(t))

        self.propagate(0, pre="yes")

        return None

walker.register(Lammps)

if __name__ == "__main__":
    print 'The lammpsWalker module is a subclass of walker:', issubclass(Lammps, walker)