def __abs__(self):
"""return an :class:`AbsoluteValue` object, or a smooth approximation"""
k = pybamm.settings.abs_smoothing
# Return exact approximation if that is the setting or the outcome is a constant
# (i.e. no need for smoothing)
if k == "exact" or is_constant(self):
out = pybamm.AbsoluteValue(self)
else:
out = pybamm.smooth_absolute_value(self, k)
return pybamm.simplify_if_constant(out, keep_domains=True)
def test_smooth_absolute_value(self):
a = pybamm.StateVector(slice(0, 1))
expr = pybamm.smooth_absolute_value(a, 10)
self.assertAlmostEqual(expr.evaluate(y=np.array([1]))[0, 0], 1)
self.assertEqual(expr.evaluate(y=np.array([0])), 0)
self.assertAlmostEqual(expr.evaluate(y=np.array([-1]))[0, 0], 1)
self.assertEqual(
str(expr),
"y[0:1] * (exp(10.0 * y[0:1]) - exp(-10.0 * y[0:1])) "
"/ (exp(10.0 * y[0:1]) + exp(-10.0 * y[0:1]))",
)
def test_smooth_absolute_value(self):
# Test that smooth absolute value is used when the setting is changed
a = pybamm.Symbol("a")
pybamm.settings.abs_smoothing = 10
self.assertEqual(str(abs(a)), str(pybamm.smooth_absolute_value(a, 10)))
# But exact absolute value should still be used for constants
a = pybamm.Scalar(-5)
self.assertEqual(str(abs(a)), str(pybamm.Scalar(5)))
# Change setting back for other tests
pybamm.settings.abs_smoothing = "exact"
def __abs__(self):
"""return an :class:`AbsoluteValue` object, or a smooth approximation."""
if isinstance(self, pybamm.AbsoluteValue):
# No need to apply abs a second time
return self
elif isinstance(self, pybamm.Broadcast):
# Move absolute value inside the broadcast
# Apply recursively
abs_self_not_broad = pybamm.simplify_if_constant(
abs(self.orphans[0]))
return self._unary_new_copy(abs_self_not_broad)
else:
k = pybamm.settings.abs_smoothing
# Return exact approximation if that is the setting or the outcome is a
# constant (i.e. no need for smoothing)
if k == "exact" or is_constant(self):
out = pybamm.AbsoluteValue(self)
else:
out = pybamm.smooth_absolute_value(self, k)
return pybamm.simplify_if_constant(out)