Engine Graph

class eagerx.core.graph_engine.EngineGraph(state)[source]
add(nodes)[source]

Add nodes to the graph.

Parameters:

nodes (Union[NodeSpec, List[NodeSpec]]) – Nodes/objects to add.

Return type:

None

add_component(entry)[source]

Selects an available component entry (e.g. input, output, etc…) that was not already selected.

Parameters:

entry (SpecView) – Selects the entry, so that it can be connected.

Return type:

None

connect(source=None, target=None, actuator=None, sensor=None, window=None, delay=None, skip=None)[source]

Connect an actuator/source to a sensor/target.

Parameters:

  • source (Optional[SpecView]) – Compatible source type is outputs.

  • target (Optional[SpecView]) – Compatible target type is inputs.

  • actuator (Optional[str]) – String name of the actuator.

  • sensor (Optional[str]) – String name of the sensor.

  • window (Optional[int]) –

    A non-negative number that specifies the number of messages to pass to the node’s callback().

    • window = 1: Only the last received input message.

    • window = x > 1: The trailing last x received input messages.

    • window = 0: All input messages received since the last call to the node’s callback().

    Note

    With window = 0, the number of input messages may vary and can even be zero.

  • delay (Optional[float]) – A non-negative simulated delay (seconds). This delay is ignored if simulate_delays = True in the engine’s spec().

  • skip (Optional[bool]) – Skip the dependency on this input during the first call to the node’s callback(). May be necessary to ensure that the connected graph is directed and acyclic.

Return type:

None

disconnect(source=None, target=None, actuator=None, sensor=None)[source]

Disconnect an actuator/source from a sensor/target.

Parameters:

  • source (Optional[SpecView]) – Compatible source type is outputs.

  • target (Optional[SpecView]) – Compatible target type is inputs.

  • actuator (Optional[str]) – String name of the actuator.

  • sensor (Optional[str]) – String name of the sensor.

Return type:

None

get(entry=None, actuator=None, sensor=None, parameter=None)[source]

Fetches the parameters of a node/actuator/sensor.

Parameters:

  • entry (Union[SpecView, EntitySpec, None]) – The entry whose parameters are fetched.

  • actuator (Optional[str]) – Actuator name whose parameters are fetched.

  • sensor (Optional[str]) – Sensor name whose parameters are fetched.

  • parameter (Optional[str]) – If only a single parameter needs to be fetched.

Return type:

Any

Returns:

Parameters

get_spec(name)[source]

Get Spec from the graph

Parameters:

name (str) – Name

Return type:

NodeSpec

Returns:

The specification of the entity.

gui(interactive=True, resolution=None, filename=None)[source]

Opens a graphical user interface of the graph.

Note

Requires eagerx-gui:

pip3 install eagerx-gui
Parameters:

  • interactive (Optional[bool]) – If True, an interactive application is launched. Otherwise, an RGB render of the GUI is returned. This could be useful when using a headless machine.

  • resolution (Optional[List[int]]) – Specifies the resolution of the returned render when interactive is False. If interactive is True, this argument is ignored.

  • filename (Optional[str]) – If provided, the GUI is rendered to an svg file with this name. If interactive is True, this argument is ignored.

Return type:

Optional[ndarray]

Returns:

RGB render of the GUI if interactive is False.

is_valid(plot=True)[source]

Checks the validity of the graph.

  • Checks if all selected inputs are connected.

  • Checks if the graph is directed and acyclic.

Parameters:

plot – Flag to plot the graph. Can be helpful to identify cycles in the graph that break the required acyclic property.

Return type:

bool

Returns:

flag that specifies the validity of the graph.

register()[source]

Returns the nodes that make up this subgraph, and their relation to the registered actuators and sensors.

remove(names)[source]

Removes a node from the graph.

  • First, all associated connections are disconnected.

  • Then, removes the nodes/objects.

Parameters:

names (Union[str, EntitySpec, List[Union[str, EntitySpec]]]) – Either the name or spec of the node/object that is to be removed.

Return type:

None

remove_component(entry)[source]

Deselects a component entry (e.g. input, output, etc…) that was selected.

  • First, all associated connections are disconnected.

  • Then, deselects the component entry.

Parameters:

entry (SpecView) – Deselects the entry.

Return type:

None

set(mapping, entry, parameter=None)[source]

Sets the parameters of a node.

Parameters:

  • mapping (Any) – Either a mapping with key = parameter, or a single value that corresponds to the optional parameter argument.

  • entry (Optional[SpecView]) – The entry whose parameters are mutated.

  • parameter (Optional[str]) – If only a single value needs to be set. See documentation for mapping.

Return type:

None