How to compute the product some of parts of two vectors
If it's just that simple do:
sum([A[i]*B[i] for i in range(3)])
This sums the products of the first three values with each other.
Hope this helps!
How can I compute the product sum of the first three elements of two vectors 
A = [a1, a2, a3, a4, a5, a6]andB = [b1, b2, b3, b4, b5, b6] (i.e. [a1b1 + a2b2 + a3b3])in python and tensorflow.