pywr.nodes.Storage

class pywr.nodes.Storage(*args, **kwargs)

A generic storage Node

In terms of connections in the network the Storage node behaves like any other node, provided there is only 1 input and 1 output. If there are multiple sub-nodes the connections need to be explicit about which they are connecting to. For example:

>>> storage(model, 'reservoir', num_outputs=1, num_inputs=2)
>>> supply.connect(storage)
>>> storage.connect(demand1, from_slot=0)
>>> storage.connect(demand2, from_slot=1)

The attribtues of the sub-nodes can be modified directly (and independently). For example:

>>> storage.outputs[0].max_flow = 15.0

If a recorder is set on the storage node, instead of recording flow it records changes in storage. Any recorders set on the output or input sub-nodes record flow as normal.

Parameters

modelModel

Model instance to which this storage node is attached.

namestr

The name of the storage node.

num_inputs, num_outputsinteger (optional)

The number of input and output nodes to create internally. Defaults to 1.

min_volumefloat (optional)

The minimum volume of the storage. Defaults to 0.0.

max_volumefloat, Parameter (optional)

The maximum volume of the storage. Defaults to 0.0.

initial_volume, initial_volume_pcfloat (optional)

Specify initial volume in either absolute or proportional terms. Both are required if max_volume is a parameter because the parameter will not be evaluated at the first time-step. If both are given and max_volume is not a Parameter, then the absolute value is ignored.

costfloat, Parameter (optional)

The cost of net flow in to the storage node. I.e. a positive cost penalises increasing volume by giving a benefit to negative net flow (release), and a negative cost penalises decreasing volume by giving a benefit to positive net flow (inflow).

area, levelfloat, Parameter (optional)

Optional float or Parameter defining the area and level of the storage node. These values are accessible through the get_area and get_level methods respectively.

__init__(model, name, num_outputs=1, num_inputs=1, *args, **kwargs)

Initialize self. See help(type(self)) for accurate signature.

Methods

__init__(model, name[, num_outputs, num_inputs])	Initialize self.
after(self, Timestep ts, double[)
before(self, Timestep ts)	Called at the beginning of the timestep
check(self)
commit(self, int scenario_index, double value)	Called once for each route the node is a member of
commit_all(self, double[)	Called once for each route the node is a member of
connect(node[, from_slot, to_slot])	Create an edge from this Node to another Node
disconnect([node, slot_name, all_slots])	Remove a connection from this Node to another Node
finish(self)
get_area(self, ScenarioIndex scenario_index)
get_cost(self, ScenarioIndex scenario_index)	Get the cost per unit flow at a given timestep
get_initial_pc(self)	Returns the initial volume as a proportion.
get_initial_volume(self)	Returns the absolute initial volume.
get_level(self, ScenarioIndex scenario_index)
get_max_volume(self, …)
get_min_volume(self, …)
iter_slots([slot_name, is_connector, all_slots])	Returns the object(s) wich should be connected to given slot_name
load(data, model)
reset(self)	Called at the beginning of a run
setup(self, model)	Called before the first run of the model

Attributes

allow_isolated	A property to flag whether this Node can be unconnected in a network.
area
comment	comment: basestring
component_attrs
components	Generator that returns all of the Components attached to the Node
cost	The cost per unit increased in volume stored
current_pc	Current percentage full
domain
flow	Total flow via this node in the current timestep
fully_qualified_name
initial_volume
initial_volume_pc
level
max_volume
min_volume
model	The recorder for the node, e.g.
name	Name of the node.
parent	The parent Node/Storage of this object.
prev_flow	Total flow via this node in the previous timestep
recorders	Returns a list of pywr.recorders.Recorder objects attached to this node.
virtual	virtual: ‘bool’
volume