Difference between numpy.dot and a.dot(b)

python numpy matrix-multiplication
McLawrence picture McLawrence · Feb 28, 2017 · Viewed 12.6k times · Source

Is there a difference between

import numpy as np
np.dot(a,b)

and

a.dot(b)

internally? I wasn't able to find any documentation on the latter method.

Answer

user2357112 supports Monica picture user2357112 supports Monica · Dec 9, 2017

If a is an array, they're equivalent. The docs you couldn't find for the dot method are here, and they boil down to "see numpy.dot".

If type(a) is not numpy.ndarray, then numpy.dot will convert a to an array and use the array for the multiplication, while a.dot will do whatever a's type says it does, or raise an AttributeError if a doesn't have a dot method.

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