feat(MLRsearch): MLRsearch v7

Replaces MLRv2, suitable for "big bang" upgrade across CSIT.
PyPI metadata updated only partially (full edits will come separately).
Pylint wants less complexity, but the differences are only minor.

+ Use the same (new CSIT) defaults everywhere, also in Python library.
+ Update also PLRsearch to use the new result class.
+ Make upper bound optional in UTI.
+ Fix ASTF approximate duration detection.
+ Do not keep approximated_receive_rate (for MRR) in result structure.

Change-Id: I03406f32d5c93f56b527cb3f93791b61955dfd74
Signed-off-by: Vratko Polak <vrpolak@cisco.com>

1 files changed, 83 insertions, 0 deletions

diff --git a/resources/libraries/python/MLRsearch/strategy/halve.py b/resources/libraries/python/MLRsearch/strategy/halve.py
new file mode 100644
index 0000000000..3188a041c6
--- /dev/null
+++ b/resources/libraries/python/MLRsearch/strategy/halve.py
@@ -0,0 +1,83 @@
+# Copyright (c) 2023 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 HalveStrategy class."""
+
+
+from dataclasses import dataclass
+from typing import Optional, Tuple
+
+from ..discrete_interval import DiscreteInterval
+from ..discrete_load import DiscreteLoad
+from ..discrete_width import DiscreteWidth
+from ..relevant_bounds import RelevantBounds
+from .base import StrategyBase
+
+
+@dataclass
+class HalveStrategy(StrategyBase):
+    """First strategy to apply for a new current target.
+
+    Pick a load between initial lower bound and initial upper bound,
+    nominate it if it is (still) worth it.
+
+    In a sense, this can be viewed as an extension of preceding target's
+    bisect strategy. But as the current target may require a different
+    trial duration, it is better to do it for the new target.
+
+    Alternatively, this is a way to save one application
+    of subsequent refine strategy, thus avoiding reducing risk of triggering
+    an external search (slight time saver for highly unstable SUTs).
+    Either way, minor time save is achieved by preceding target
+    only needing to reach double of current target width.
+
+    If the distance between initial bounds is already at or below
+    current target width, the middle point is not nominated.
+    The reasoning is that in this case external search is likely
+    to get triggered by the subsequent refine strategies,
+    so attaining a relevant bound here is not as likely to help.
+    """
+
+    def nominate(
+        self, bounds: RelevantBounds
+    ) -> Tuple[Optional[DiscreteLoad], Optional[DiscreteWidth]]:
+        """Nominate the middle between initial lower and upper bound.
+
+        The returned width is the target width, even if initial bounds
+        happened to be closer together.
+
+        :param bounds: Freshly updated bounds relevant for current target.
+        :type bounds: RelevantBounds
+        :returns: Two nones or candidate intended load and duration.
+        :rtype: Tuple[Optional[DiscreteLoad], Optional[DiscreteWidth]]
+        """
+        if not self.initial_lower_load or not self.initial_upper_load:
+            return None, None
+        interval = DiscreteInterval(
+            lower_bound=self.initial_lower_load,
+            upper_bound=self.initial_upper_load,
+        )
+        wig = interval.width_in_goals(self.target.discrete_width)
+        if wig > 2.0:
+            # Can happen for initial target.
+            return None, None
+        if wig <= 1.0:
+            # Already was narrow enough, refinements shall be sufficient.
+            return None, None
+        load = interval.middle(self.target.discrete_width)
+        if self.not_worth(bounds, load):
+            return None, None
+        self.debug(f"Halving available: {load}")
+        # TODO: Report possibly smaller width?
+        self.expander.limit(self.target.discrete_width)
+        return load, self.target.discrete_width