Run datporod and return the estimated Porod volume.

    Returns:
         Radius of gyration found in the input file
         I0 found in the input file
         Vporod: the estimated Porod volume

def datporod(gnomoutfile):
    """Run datporod and return the estimated Porod volume.

    Returns:
         Radius of gyration found in the input file
         I0 found in the input file
         Vporod: the estimated Porod volume
    """
    results = subprocess.check_output(['datporod', gnomoutfile]).decode('utf-8').strip().split()
    return float(results[0]), float(results[1]), float(results[2])