def processAlgorithm(self, parameters, context: QgsProcessingContext,
feedback: QgsProcessingFeedback):
"""Here is where the processing itself takes place."""
feedback.setProgress(0)
# init params
reach_layer = self.parameterAsVectorLayer(parameters, self.REACH_LAYER,
context)
wastewater_node_layer = self.parameterAsVectorLayer(
parameters, self.WASTEWATER_NODE_LAYER, context)
value_expression = self.parameterAsExpression(parameters,
self.VALUE_EXPRESSION,
context)
reach_pk_name = self.parameterAsFields(parameters, self.REACH_PK_NAME,
context)[0]
node_pk_name = self.parameterAsFields(parameters, self.NODE_PK_NAME,
context)[0]
node_from_fk_name = self.parameterAsFields(parameters,
self.NODE_FROM_FK_NAME,
context)[0]
node_to_fk_name = self.parameterAsFields(parameters,
self.NODE_TO_FK_NAME,
context)[0]
branch_behavior = self.parameterAsEnum(parameters,
self.BRANCH_BEHAVIOR, context)
create_loop_layer = self.parameterAsBool(parameters,
self.CREATE_LOOP_LAYER,
context)
if branch_behavior == 0:
aggregate_method = lambda values: min(values) if values else 0
elif branch_behavior == 1:
aggregate_method = lambda values: max(values) if values else 0
elif branch_behavior == 2:
aggregate_method = lambda values: statistics.mean(
values) if values else 0
else:
aggregate_method = lambda values: feedback.pushError(
'Aggregate method not implemented')
# create feature sink
fields = wastewater_node_layer.fields()
fields.append(QgsField('value', QVariant.Double))
(sink, dest_id) = self.parameterAsSink(parameters, self.OUTPUT,
context, fields,
QgsWkbTypes.Point,
reach_layer.sourceCrs())
loop_sink = None
loop_dest_id = None
if create_loop_layer:
(loop_sink,
loop_dest_id) = self.parameterAsSink(parameters, self.LOOP_OUTPUT,
context, fields,
QgsWkbTypes.Point,
reach_layer.sourceCrs())
if sink is None:
raise QgsProcessingException(
self.invalidSinkError(parameters, self.OUTPUT))
feature_count = reach_layer.featureCount()
reaches_by_from_node = dict()
reaches_by_id = dict()
expression = QgsExpression(value_expression)
context = QgsExpressionContext(
QgsExpressionContextUtils.globalProjectLayerScopes(reach_layer))
expression.prepare(context)
progress = 0
feedback.setProgressText(self.tr('Indexing reaches'))
for reach in reach_layer.getFeatures(QgsFeatureRequest()):
if reach[node_from_fk_name] == NULL:
continue
context.setFeature(reach)
value = expression.evaluate(context)
reach_obj = Reach(reach[node_from_fk_name], reach[node_to_fk_name],
value, reach.geometry())
reaches_by_from_node.setdefault(reach_obj.from_id,
[]).append(reach_obj)
reaches_by_id[reach[reach_pk_name]] = reach_obj
feedback.setProgress(progress / feature_count * 10)
progress += 1
loop_nodes = []
current_feature = 0
calculated_values = {}
feedback.setProgressText(self.tr('Analyzing network'))
for node in wastewater_node_layer.getFeatures():
from_node_id = node[node_pk_name]
processed_nodes = []
times = []
if from_node_id in reaches_by_from_node.keys():
for reach in reaches_by_from_node[from_node_id]:
times.append(
self.calculate_branch(reach, reaches_by_from_node,
reaches_by_id,
list(processed_nodes),
calculated_values,
aggregate_method, loop_nodes,
feedback))
if times:
time = aggregate_method(times)
else:
time = 0
current_feature += 1
calculated_values[node[node_pk_name]] = time
new_node = QgsFeature(node)
new_node.setFields(fields)
new_node.setAttributes(node.attributes() + [time])
sink.addFeature(new_node, QgsFeatureSink.FastInsert)
if create_loop_layer and from_node_id in loop_nodes:
loop_sink.addFeature(node, QgsFeatureSink.FastInsert)
feedback.setProgress(10 + current_feature / feature_count * 90)
result = {self.OUTPUT: dest_id}
if create_loop_layer:
result[self.LOOP_OUTPUT] = loop_dest_id
return result
