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src/pypdevs/schedulers/schedulerChibiList.py

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+# Copyright 2014 Modelling, Simulation and Design Lab (MSDL) at 
+# McGill University and the University of Antwerp (http://msdl.cs.mcgill.ca/)
+# 
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+The Minimal List scheduler is the simplest scheduler available, 
+though it has extremely bad performance in most cases.
+
+It simply keeps a list of all models. As soon as a reschedule happens, 
+the list is checked for the minimal value, which is stored. 
+When the imminent models are requested, the lowest value that was found 
+is used to immediatelly return [], 
+or it iterates the complete list in search of models that qualify.
+"""
+
+class SchedulerChibiList(object):
+    """
+    Scheduler class itself
+    """
+    def __init__(self, models, epsilon, total_models):
+        """
+        Constructor
+
+        :param models: all models in the simulation
+        """
+        # Make a copy!
+        self.models = list(models)
+        self.minval = float('inf')
+        self.epsilon = epsilon
+        self.massReschedule([])
+
+    def schedule(self, model):
+        """
+        Schedule a model
+
+        :param model: the model to schedule
+        """
+        self.models.append(model)
+        if model.time_next < self.minval:
+            self.minval = model.time_next
+
+    def unschedule(self, model):
+        """
+        Unschedule a model
+
+        :param model: model to unschedule
+        """
+        self.models.remove(model)
+        if model.time_next == self.minval:
+            self.minval = (float('inf'), float('inf'))
+            for m in self.models:
+                if m.time_next < self.minval:
+                    self.minval = m.time_next
+
+    def massReschedule(self, reschedule_set):
+        """
+        Reschedule all models provided. 
+        Equivalent to calling unschedule(model); schedule(model) on every element in the iterable.
+
+        :param reschedule_set: iterable containing all models to reschedule
+        """
+        self.minval = float('inf')
+        for m in self.models:
+            if m.time_next < self.minval:
+                self.minval = m.time_next
+
+    def readFirst(self):
+        """
+        Returns the time of the first model that has to transition
+
+        :returns: timestamp of the first model
+        """
+        return self.minval
+
+    def getImminent(self, t):
+        """
+        Returns a list of all models that transition at the provided time, with the specified epsilon deviation allowed.
+
+        :param time: timestamp to check for models
+
+        .. warning:: For efficiency, this method only checks the **first** elements, so trying to invoke this function with a timestamp higher than the value provided with the *readFirst* method, will **always** return an empty set.
+        """
+        imm_children = []
+        for model in self.models:
+            if abs(model.time_next - t) < self.epsilon:
+                imm_children.append(model)
+        return imm_children