Source code for spinn_utilities.find_max_success
# Copyright (c) 2019 The University of Manchester
#
# 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
#
# https://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.
[docs]def find_max_success(max_possible, check):
"""
Finds the maximum value that will pass the check
:param max_possible: The maximum value that should be tested.
:type max_possible: int
:param check: A boolean function that given an int value returns
True for every value up and including the cut-off and
False for every value greater than the cut-off
:type check: ~typing.Callable[[int], bool]
:return: The highest value that returns true for the check
but is not more than the max_possible
"""
# Check the max to avoid multiple steps if that works
if check(max_possible):
return max_possible
return search_for_max_success(0, max_possible, check)
[docs]def search_for_max_success(best_success, min_fail, check):
"""
Finds the maximum value in the range that pass the check
:param best_success: A minimum value that needs not be tested because it
is either known to succeed or is a flag for total failure.
Can be negative
:type best_success: int
:param min_fail: A maximum value that needs not be tested because it
is either known to fail or one more than the maximum interesting value
but must be greater than best_success but may also be negative
:type min_fail: int
:param check: A boolean function that given an int value returns
True for every value up and including the cut-off and
False for every value greater than the cut-off
:type check: ~typing.Callable[[int], bool]
:return: The highest value that returns true in the range between
`best_success` and `min_fail` (both exclusive ends) or `best_success`
if the whole range fails or is empty.
"""
# Check if there are still values in the middle to check
if best_success >= min_fail - 1:
return best_success
# Find the middle
mid_point = (best_success + min_fail) // 2
# Check the middle
if check(mid_point):
# Best it the middle or more
return search_for_max_success(mid_point, min_fail, check)
else:
# Best it the less than the middle
return search_for_max_success(best_success, mid_point, check)