def variable(self, o):
e, l = o.ufl_operands # noqa: E741
v = self.variable_map.get(l)
if v is None:
e = self.visit(e)
l2 = Label(len(self.variable_map))
v = Variable(e, l2)
self.variable_map[l] = v
return v
def variable(self, o):
# Check cache
e, l = o.operands()
c = self._variable_cache.get(l)
if c is not None:
return c
if o.label() == self._variable.label():
# dv/dv = "1"
op = self._make_ones_diff(o)
else:
# differentiate expression behind variable
e2, ep = self.visit(e)
op = ep
if not e2 == e:
o = Variable(e2, l)
# return variable and derivative of its expression
c = (o, op)
self._variable_cache[l] = c
return c
def variable(e):
"""UFL operator: Define a variable representing the given expression, see also
``diff()``."""
e = as_ufl(e)
return Variable(e)