Why is statistics.mean() so slow?

Python’s statistics module is not built for speed, but for precision In the specs for this module, it appears that The built-in sum can lose accuracy when dealing with floats of wildly differing magnitude. Consequently, the above naive mean fails this “torture test” assert mean([1e30, 1, 3, -1e30]) == 1 returning 0 instead of 1, … Read more

What is the difference between np.mean and tf.reduce_mean?

The functionality of numpy.mean and tensorflow.reduce_mean are the same. They do the same thing. From the documentation, for numpy and tensorflow, you can see that. Lets look at an example, c = np.array([[3.,4], [5.,6], [6.,7]]) print(np.mean(c,1)) Mean = tf.reduce_mean(c,1) with tf.Session() as sess: result = sess.run(Mean) print(result) Output [ 3.5 5.5 6.5] [ 3.5 5.5 … Read more

Calculate mean and standard deviation from a vector of samples in C++ using Boost

I don’t know if Boost has more specific functions, but you can do it with the standard library. Given std::vector<double> v, this is the naive way: #include <numeric> double sum = std::accumulate(v.begin(), v.end(), 0.0); double mean = sum / v.size(); double sq_sum = std::inner_product(v.begin(), v.end(), v.begin(), 0.0); double stdev = std::sqrt(sq_sum / v.size() – mean … Read more

group by in group by and average

If you want to first take mean on the combination of [‘cluster’, ‘org’] and then take mean on cluster groups, you can use: In [59]: (df.groupby([‘cluster’, ‘org’], as_index=False).mean() .groupby(‘cluster’)[‘time’].mean()) Out[59]: cluster 1 15 2 54 3 6 Name: time, dtype: int64 If you want the mean of cluster groups only, then you can use: In … Read more

np.mean() vs np.average() in Python NumPy?

np.average takes an optional weight parameter. If it is not supplied they are equivalent. Take a look at the source code: Mean, Average np.mean: try: mean = a.mean except AttributeError: return _wrapit(a, ‘mean’, axis, dtype, out) return mean(axis, dtype, out) np.average: … if weights is None : avg = a.mean(axis) scl = avg.dtype.type(a.size/avg.size) else: #code … Read more

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