# Source code for pm4py.objects.bpmn.util.reduction

```
'''
This file is part of PM4Py (More Info: https://pm4py.fit.fraunhofer.de).
PM4Py is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
PM4Py is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with PM4Py. If not, see <https://www.gnu.org/licenses/>.
'''
from pm4py.objects.bpmn.obj import BPMN
[docs]def reduce_xor_gateways(bpmn_graph, parameters=None):
"""
Reduces the number of XOR gateways in the diagram
Parameters
------------
bpmn_graph
BPMN graph
parameters
Parameters
Returns
------------
bpmn_graph
(possibly reduced) BPMN graph
"""
if parameters is None:
parameters = {}
changed = True
while changed:
changed = False
outgoing_edges = None
incoming_edges = None
outgoing_edges = {}
incoming_edges = {}
for flow in bpmn_graph.get_flows():
source = flow.get_source()
target = flow.get_target()
if source not in outgoing_edges:
outgoing_edges[source] = set()
outgoing_edges[source].add(flow)
if target not in incoming_edges:
incoming_edges[target] = set()
incoming_edges[target].add(flow)
nodes = list(bpmn_graph.get_nodes())
for node in nodes:
if isinstance(node, BPMN.ExclusiveGateway):
if node in outgoing_edges and node in incoming_edges and len(outgoing_edges[node]) == 1 and len(
incoming_edges[node]) == 1:
changed = True
source_node = None
target_node = None
for flow in incoming_edges[node]:
source_node = flow.get_source()
if flow in bpmn_graph.get_flows():
bpmn_graph.remove_flow(flow)
for flow in outgoing_edges[node]:
target_node = flow.get_target()
if flow in bpmn_graph.get_flows():
bpmn_graph.remove_flow(flow)
if node in bpmn_graph.get_nodes():
bpmn_graph.remove_node(node)
bpmn_graph.add_flow(BPMN.Flow(source_node, target_node))
break
return bpmn_graph
[docs]def apply(bpmn_graph, parameters=None):
"""
Reduce the complexity of a BPMN graph by removing useless elements
Parameters
------------
bpmn_graph
BPMN graph
parameters
Parameters
Returns
------------
bpmn_graph
(possibly reduced) BPMN graph
"""
if parameters is None:
parameters = {}
bpmn_graph = reduce_xor_gateways(bpmn_graph, parameters=parameters)
return bpmn_graph
```