pd.rolling_mean becoming deprecated - alternatives for ndarrays

Question

EDIT: This question was asked in 2016 and similar questions have been posted on SO years later after the functionality was finally removed, e.g. module 'pandas' has

Answer 1

Looks like the new way is via methods on the DataFrame.rolling class (I guess you're meant to think of it sort of like a groupby): http://pandas.pydata.org/pandas-docs/version/0.18.0/whatsnew.html

e.g.

x.rolling(window=2).mean()

Answer 2

EDIT -- Unfortunately, it looks like the new way is not nearly as fast:

New version of Pandas:

In [1]: x = np.random.uniform(size=100)

In [2]: %timeit pd.rolling_mean(x, window=2)
1000 loops, best of 3: 240 µs per loop

In [3]: %timeit pd.Series(x).rolling(window=2).mean()
1000 loops, best of 3: 226 µs per loop

In [4]: pd.__version__
Out[4]: '0.18.0'

Old version:

In [1]: x = np.random.uniform(size=100)

In [2]: %timeit pd.rolling_mean(x,window=2)
100000 loops, best of 3: 12.4 µs per loop

In [3]: pd.__version__
Out[3]: u'0.17.1'

Answer 3

try this

x.rolling(window=2, center=False).mean()

Answer 4

I suggest scipy.ndimage.filters.uniform_filter1d like in my answer to the linked question. It is also way faster for large arrays:

import numpy as np
from scipy.ndimage.filters import uniform_filter1d
N = 1000
x = np.random.random(100000)

%timeit pd.rolling_mean(x, window=N)
__main__:257: FutureWarning: pd.rolling_mean is deprecated for ndarrays and will be removed in a future version
The slowest run took 84.55 times longer than the fastest. This could mean that an intermediate result is being cached.
1 loop, best of 3: 7.37 ms per loop

%timeit uniform_filter1d(x, size=N)
10000 loops, best of 3: 190 µs per loop

Answer 5

If your dimensions are homogeneous, you could try to implement an n-dimensional form of the Summed Area Table used for bidimensional images:

A summed area table is a data structure and algorithm for quickly and efficiently generating the sum of values in a rectangular subset of a grid.

Then, in this order, you could:

1. Create the summed area table ("integral") of your array;
2. Iterate to get the (quite cheap) sum of a n-dimensional kernel at a given position;
3. Divide by the size of the n-dimensional volume of the kernel.

Unfortunately I cannot know if this is efficient or not, but the by the given premise, it should be.