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