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EthanRosenthal/stacking_matrices.py

Last active February 7, 2018 15:11
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Lazily stack matrices
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stacking_matrices.py
import numpy as np
"""Stacking as we loop"""
%%timeit -n 10
res = None
for i in range(100):
batch = np.random.random((100, 100))
if res is None:
res = batch
else:
res = np.vstack((res, batch))
# 279 ms ± 15 ms per loop (mean ± std. dev. of 7 runs, 10 loops each)
"""Stacking after the loop"""
%%timeit -n 10
res = []
for i in range(100):
res.append(np.random.random((100, 100)))
res = np.vstack(res)
# 14 ms ± 657 µs per loop (mean ± std. dev. of 7 runs, 10 loops each)
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