spinetoolbox.dag_handler

Contains classes for handling DAGs.

author:
  1. Savolainen (VTT)
date:

8.4.2019

Module Contents

class spinetoolbox.dag_handler.DirectedGraphHandler[source]

Bases: PySide2.QtCore.QObject

Class for manipulating graphs according to user’s actions.

dag_simulation_requested[source]
dags(self)[source]

Returns a list of graphs (DiGraph) in the project.

add_dag(self, dag, request_simulation=True)[source]

Add graph to list.

Parameters:
  • dag (DiGraph) – Graph to add
  • request_simulation (bool) – if True, emits dag_simulation_requested
remove_dag(self, dag)[source]

Remove graph from instance variable list.

Parameters:dag (DiGraph) – Graph to remove
add_dag_node(self, node_name)[source]

Create directed graph with one node and add it to list.

Parameters:node_name (str) – Project item name to add as a node
add_graph_edge(self, src_node, dst_node)[source]

Adds an edge between the src and dst nodes. If nodes are in different graphs, the reference to union graph is saved and the references to the original graphs are removed. If src and dst nodes are already in the same graph, the edge is added to the graph. If src and dst are the same node, a self-loop (feedback) edge is added.

Parameters:
  • src_node (str) – Source project item node name
  • dst_node (str) – Destination project item node name
remove_graph_edge(self, src_node, dst_node)[source]

Removes edge from a directed graph.

Parameters:
  • src_node (str) – Source project item node name
  • dst_node (str) – Destination project item node name
remove_node_from_graph(self, node_name)[source]

Removes node from a graph that contains it. Called when project item is removed from project.

Parameters:node_name (str) – Project item name
rename_node(self, old_name, new_name)[source]

Handles renaming the node and edges in a graph when a project item is renamed.

Parameters:
  • old_name (str) – Old project item name
  • new_name (str) – New project item name
Returns:

True if successful, False if renaming failed
Return type:

bool
dag_with_node(self, node_name)[source]

Returns directed graph that contains given node.

Parameters:node_name (str) – Node to look for
Returns:Directed graph that contains node or None if not found.
Return type:(DiGraph)
dag_with_edge(self, src_node, dst_node)[source]

Returns directed graph that contains given edge.

Parameters:
  • src_node (str) – Source node name
  • dst_node (str) – Destination node name
Returns:

Directed graph that contains edge or None if not found.
Return type:

(DiGraph)
static node_successors(g)[source]

Returns a dict mapping nodes in the given graph to a list of its direct successors. The nodes are in topological sort order. Topological sort in the words of networkx: “a nonunique permutation of the nodes, such that an edge from u to v implies that u appears before v in the topological sort order.”

Parameters:g (DiGraph) – Directed graph to process
Returns:key is the node name, value is list of successor names Empty dict if given graph is not a DAG.
Return type:dict
successors_til_node(self, g, node)[source]

Like node_successors but only until the given node, and ignoring all nodes that are not its ancestors.

node_is_isolated(self, node, allow_self_loop=False)[source]

Checks if the project item with the given name has any connections.

Parameters:
  • node (str) – Project item name
  • allow_self_loop (bool) – If default (False), Self-loops are considered as an in-neighbor or an out-neighbor so the method returns False. If True, single node with a self-loop is considered isolated.
Returns:

True if project item has no in-neighbors nor out-neighbors, False if it does.

Single node with a self-loop is NOT isolated (returns False).
Return type:

bool
static source_nodes(g)[source]

Returns a list of source nodes in given graph. A source node has no incoming edges. This is determined by calculating the in-degree of each node in the graph. If nodes in-degree == 0, it is a source node

Parameters:g (DiGraph) – Graph to examine
Returns:List of source node names or an empty list is there are none.
Return type:list
static edges_causing_loops(g)[source]

Returns a list of edges whose removal from g results in it becoming acyclic.

static export_to_graphml(g, path)[source]

Export given graph to a path in GraphML format.

Parameters:
  • g (DiGraph) – Graph to export
  • path (str) – Full output path for GraphML file
Returns:

Operation success status
Return type:

bool
receive_item_execution_finished(self, item_finish_state)[source]

TODO: Method obsolete? Pop next project item to execute or finish current graph if there are no items left.

Parameters:item_finish_state (ExecutionState) – an enumeration to indicate if execution should continue or not