diff --git a/bareon_dynamic_allocator/sequences.py b/bareon_dynamic_allocator/sequences.py new file mode 100644 index 0000000..a3d180d --- /dev/null +++ b/bareon_dynamic_allocator/sequences.py @@ -0,0 +1,67 @@ +# Copyright 2016 Mirantis, Inc. +# +# 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 then +# License for the specific language governing permissions and limitations +# under the License. + +import math + + +class BaseSequence(object): + + def __init__(self, n): + self.n = n + self.n_current = 0 + self.current = 1 + self.previous = 0 + + def __iter__(self): + return self + + def next(self): + self.previous = self.current + self.current += 1 + return self.current + + +class CrossSumInequalitySequence(BaseSequence): + """An implementaion of a sequence from 1 to n + + http://math.stackexchange.com/a/1596812/301008 + """ + + def next(self): + if self.n_current >= self.n: + raise StopIteration + else: + self.previous = int(math.floor((self.current + 1) / 2.0) * + math.floor((self.current + 2) / 2.0)) + self.n_current += 1 + self.current += 1 + + return self.previous + + +class FibonacciSequence(BaseSequence): + """Iterator over a sequence of Fibonacci numbers with n elements from 1 to n + """ + def __init__(self, n): + super(FibonacciSequence, self).__init__(n) + self.previous = 0 + self.current = 1 + + def next(self): + if self.n_current > self.n: + raise StopIteration + else: + self.n_current += 1 + self.previous, self.current = self.current, self.current + self.previous + return self.current