def _parameters_from_synapse_type(self, projection, distance_map=None):
"""
Obtain the parameters to be used for the connections from the projection's `synapse_type`
attribute. Each parameter value is a `LazyArray`.
"""
if distance_map is None:
distance_map = Connector._generate_distance_map(self, projection)
parameter_space = projection.synapse_type.native_parameters
# TODO: in the documentation, we claim that a parameter value can be
# a list or 1D array of the same length as the number of connections.
# We do not currently handle this scenario, although it is only
# really useful for fixed-number connectors anyway.
# Probably the best solution is to remove the parameter at this stage,
# then set it after the connections have already been created.
parameter_space.shape = (projection.pre.size, projection.post.size)
# Remove randomly generated variables from the (host) parameter_space
# if the user so chooses. We keep a copy of the removed (not expanded)
# parameters in the Connector object
pops = []
for name, map in parameter_space.items():
# if len(map.operations):
# continue
if ((isinstance(map.base_value, RandomDistribution)
and isinstance(map.base_value.rng, NativeRNG))
or map.is_homogeneous):
self.on_device_init_params[name] = map
pops.append(name)
for name in pops:
parameter_space.pop(name)
for name, map in parameter_space.items():
if callable(map.base_value):
if isinstance(map.base_value, IndexBasedExpression):
# Assumes map is a function of index and hence requires the projection to
# determine its value. It and its index function are copied so as to be able
# to set the projection without altering the connector, which would perhaps
# not be expected from the 'connect' call.
new_map = copy(map)
new_map.base_value = copy(map.base_value)
new_map.base_value.projection = projection
parameter_space[name] = new_map
else:
# Assumes map is a function of distance
parameter_space[name] = map(distance_map)
return parameter_space
