CSIT-986: Implement proposed MDR improvements

[csit.git] / PyPI / MLRsearch / MLRsearch / ReceiveRateInterval.py

diff --git a/PyPI/MLRsearch/MLRsearch/ReceiveRateInterval.py b/PyPI/MLRsearch/MLRsearch/ReceiveRateInterval.py
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+++ b/PyPI/MLRsearch/MLRsearch/ReceiveRateInterval.py
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+# Copyright (c) 2018 Cisco and/or its affiliates.
+# 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.
+
+"""Module defining ReceiveRateInterval class."""
+
+import math
+
+from ReceiveRateMeasurement import ReceiveRateMeasurement
+
+
+class ReceiveRateInterval(object):
+    """Structure defining two Rr measurements, and their relation."""
+
+    def __init__(self, measured_low, measured_high):
+        """Store the bound measurements after checking argument types.
+
+        :param measured_low: Measurement for the lower bound.
+        :param measured_high: Measurement for the upper bound.
+        :type measured_low: ReceiveRateMeasurement
+        :type measured_high: ReceiveRateMeasurement
+        """
+        # TODO: Type checking is not very pythonic,
+        # perhaps users can fix wrong usage without it?
+        if not isinstance(measured_low, ReceiveRateMeasurement):
+            raise TypeError("measured_low is not a ReceiveRateMeasurement: "
+                            "{low!r}".format(low=measured_low))
+        if not isinstance(measured_high, ReceiveRateMeasurement):
+            raise TypeError("measured_high is not a ReceiveRateMeasurement: "
+                            "{high!r}".format(high=measured_high))
+        self.measured_low = measured_low
+        self.measured_high = measured_high
+        # Declare secondary quantities to appease pylint.
+        self.abs_tr_width = None
+        """Absolute width of target transmit rate. Upper minus lower."""
+        self.rel_tr_width = None
+        """Relative width of target transmit rate. Absolute divided by upper."""
+        self.sort()
+
+    def sort(self):
+        """Sort bounds by target Tr, compute secondary quantities."""
+        if self.measured_low.target_tr > self.measured_high.target_tr:
+            self.measured_low, self.measured_high = (
+                self.measured_high, self.measured_low)
+        self.abs_tr_width = (
+            self.measured_high.target_tr - self.measured_low.target_tr)
+        self.rel_tr_width = self.abs_tr_width / self.measured_high.target_tr
+
+    def width_in_goals(self, relative_width_goal):
+        """Return float value.
+
+        Relative width goal is some (negative) value on logarithmic scale.
+        Current relative width is another logarithmic value.
+        Return the latter divided by the former.
+        This is useful when investigating how did surprising widths come to be.
+
+        :param relative_width_goal: Upper bound times this is the goal
+            difference between upper bound and lower bound.
+        :type relative_width_goal: float
+        :returns: Current width as logarithmic multiple of goal width [1].
+        :rtype: float
+        """
+        return math.log(1.0 - self.rel_tr_width) / math.log(
+            1.0 - relative_width_goal)
+
+    def __str__(self):
+        """Return string as half-open interval."""
+        return "[{low!s};{high!s})".format(
+            low=self.measured_low, high=self.measured_high)
+
+    def __repr__(self):
+        """Return string evaluable as a constructor call."""
+        return ("ReceiveRateInterval(measured_low={low!r}"
+                ",measured_high={high!r})".format(
+                    low=self.measured_low, high=self.measured_high))