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, 193 insertions, 0 deletions

diff --git a/resources/libraries/python/MLRsearch/strategy/bisect.py b/resources/libraries/python/MLRsearch/strategy/bisect.py
new file mode 100644
index 0000000000..894544695e
--- /dev/null
+++ b/resources/libraries/python/MLRsearch/strategy/bisect.py
@@ -0,0 +1,193 @@
+# 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 BisectStrategy 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 BisectStrategy(StrategyBase):
+    """Strategy to use when both bounds relevant to curent target are present.
+
+    Primarily, this strategy is there to perform internal search.
+    As powers of two are fiendly to binary search,
+    this strategy relies on the splitting logic described in DiscreteInterval.
+
+    The main reason why this class is so long is that a mere existence
+    of a valid bound for the current target does not imply
+    that bound is a good approximation of the final conditional throughput.
+    The bound might become valid due to efforts of a strategy
+    focusing on an entirely different search goal.
+
+    On the other hand, initial bounds may be better approximations,
+    but they also may be bad approximations (for example
+    when SUT behavior strongly depends on trial duration).
+
+    Based on comparison of existing current bounds to intial bounds,
+    this strategy also mimics what would external search do
+    (if the one current bound was missing and other initial bound was current).
+    In case that load value is closer to appropriate inital bound
+    (compared to how far the simple bisect between current bounds is),
+    that load is nominated.
+
+    It turns out those "conditional" external search nominations
+    are quite different from unconditional ones,
+    at least when it comes to handling limits
+    and tracking when width expansion should be applied.
+    That is why that logic is here
+    and not in some generic external search class.
+    """
+
+    expand_on_clo: bool = False
+    """If extending up, width should be expanded when load becomes clo."""
+    expand_on_chi: bool = False
+    """If extending down, width should be expanded when load becomes chi."""
+
+    def nominate(
+        self, bounds: RelevantBounds
+    ) -> Tuple[Optional[DiscreteLoad], Optional[DiscreteWidth]]:
+        """Nominate a load candidate between bounds or extending from them.
+
+        The external search logic is offloaded into private methods.
+        If they return a truthy load, that is returned from here as well.
+
+        Only if the actual bisect is selected,
+        the per-selector expander is limited to the (smaller) new width.
+
+        :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 bounds.clo or bounds.clo >= self.handler.max_load:
+            return None, None
+        if not bounds.chi or bounds.chi <= self.handler.min_load:
+            return None, None
+        interval = DiscreteInterval(bounds.clo, bounds.chi)
+        if interval.width_in_goals(self.target.discrete_width) <= 1.0:
+            return None, None
+        bisect_load = interval.middle(self.target.discrete_width)
+        load, width = self._extend_lo(bounds, bisect_load)
+        if load:
+            self.expand_on_clo, self.expand_on_chi = False, True
+            self.debug(f"Preferring to extend down: {load}")
+            return load, width
+        load, width = self._extend_hi(bounds, bisect_load)
+        if load:
+            self.expand_on_clo, self.expand_on_chi = True, False
+            self.debug(f"Preferring to extend up: {load}")
+            return load, width
+        load = bisect_load
+        if self.not_worth(bounds=bounds, load=load):
+            return None, None
+        self.expand_on_clo, self.expand_on_chi = False, False
+        self.debug(f"Preferring to bisect: {load}")
+        width_lo = DiscreteInterval(bounds.clo, load).discrete_width
+        width_hi = DiscreteInterval(load, bounds.chi).discrete_width
+        width = min(width_lo, width_hi)
+        self.expander.limit(width)
+        return load, width
+
+    def _extend_lo(
+        self, bounds: RelevantBounds, bisect_load: DiscreteLoad
+    ) -> Tuple[Optional[DiscreteLoad], Optional[DiscreteWidth]]:
+        """Compute load as if extending down, return it if preferred.
+
+        :param bounds: Freshly updated bounds relevant for current target.
+        :param bisect_load: Load when bisection is preferred.
+        :type bounds: RelevantBounds
+        :type bisect_load: DiscreteLoad
+        :returns: Two nones or candidate intended load and duration.
+        :rtype: Tuple[Optional[DiscreteLoad], Optional[DiscreteWidth]]
+        :raises RuntimeError: If an internal inconsistency is detected.
+        """
+        # TODO: Simplify all the conditions or explain them better.
+        if not self.initial_upper_load:
+            return None, None
+        if bisect_load >= self.initial_upper_load:
+            return None, None
+        width = self.expander.get_width()
+        load = bounds.chi - width
+        load = self.handler.handle(
+            load=load,
+            width=self.target.discrete_width,
+            clo=bounds.clo,
+            chi=bounds.chi,
+        )
+        if not load:
+            return None, None
+        if load <= bisect_load:
+            return None, None
+        if load >= self.initial_upper_load:
+            return None, None
+        if self.not_worth(bounds=bounds, load=load):
+            raise RuntimeError(f"Load not worth: {load}")
+        return load, width
+
+    def _extend_hi(
+        self, bounds: RelevantBounds, bisect_load: DiscreteLoad
+    ) -> Tuple[Optional[DiscreteLoad], Optional[DiscreteWidth]]:
+        """Compute load as if extending up, return it if preferred.
+
+        :param bounds: Freshly updated bounds relevant for current target.
+        :param bisect_load: Load when bisection is preferred.
+        :type bounds: RelevantBounds
+        :type bisect_load: DiscreteLoad
+        :returns: Two nones or candidate intended load and duration.
+        :rtype: Tuple[Optional[DiscreteLoad], Optional[DiscreteWidth]]
+        :raises RuntimeError: If an internal inconsistency is detected.
+        """
+        # TODO: Simplify all the conditions or explain them better.
+        if not self.initial_lower_load:
+            return None, None
+        if bisect_load <= self.initial_lower_load:
+            return None, None
+        width = self.expander.get_width()
+        load = bounds.clo + width
+        load = self.handler.handle(
+            load=load,
+            width=self.target.discrete_width,
+            clo=bounds.clo,
+            chi=bounds.chi,
+        )
+        if not load:
+            return None, None
+        if load >= bisect_load:
+            return None, None
+        if load <= self.initial_lower_load:
+            return None, None
+        if self.not_worth(bounds=bounds, load=load):
+            raise RuntimeError(f"Load not worth: {load}")
+        return load, width
+
+    def won(self, bounds: RelevantBounds, load: DiscreteLoad) -> None:
+        """Expand width when appropriate.
+
+        :param bounds: Freshly updated bounds relevant for current target.
+        :param load: The current load, so strategy does not need to remember.
+        :type bounds: RelevantBounds
+        :type load: DiscreteLoad
+        """
+        if self.expand_on_clo and load == bounds.clo:
+            self.expander.expand()
+        elif self.expand_on_chi and load == bounds.chi:
+            self.expander.expand()