"""SI absolute error floors shared by both native code generators.

Mass must not inherit the energy floor: 1e-8 kg overwhelmed relative error
control in small pipe volumes. These conservative defaults were validated on
the pipe and chamber regressions; model-scale/user tolerance settings remain
a separate protocol change.
"""


def state_absolute_tolerance(key: str) -> str:
    field = key.rsplit('.', 1)[-1]
    if field in ('m', 'm1', 'm2'):
        return '1e-14'  # kg
    if field in ('v', 'x'):
        return '1e-12'  # m/s or m
    if field == '_volume_displacement':
        return '1e-14'  # m3, prescribed external volume change
    return '1e-8'  # J (or the internal constant state of an algebraic model)