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fibonacci.py
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fibonacci.py
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# Copyright [2018] [Haibo Yan]
#
# 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.
import numpy as np
class Fibonnaci:
def __init__(self):
a = [[1, 1], [1, 0]]
self._cache = {1:np.array(a)}
k = 1
for i in range(2, 8):
n = self._cache[k].dot(self._cache[k])
k *= 2
print(k)
self._cache[k] = n
def nth(self, n):
if n == 1 or n == 2:
return 1
n -= 1
v = n & -n
m = self._cache[v]
n -= v
while n != 0:
v = n & -n
m = m.dot(self._cache[v])
n -= v
return m[0][0]