Brain Dump

Machine Learning

Numpy

Updated at: 13 Mar 2019 05:03:36

Applying a functon on each element in the np array

Vectorizing a function, apply the function on each element in the numpy array.

https://stackoverflow.com/questions/7701429/efficient-evaluation-of-a-function-at-every-cell-of-a-numpy-array

$$x = \begin{bmatrix} 0 & 3 & 4 \ 2 & 6 & 4 \ \end{bmatrix}\tag{3}$$ then $$| x| = np.linalg.norm(x, axis = 1, keepdims = True) = \begin{bmatrix} 5 \ \sqrt{56} \ \end{bmatrix}\tag{4} $$and $$ x_normalized = \frac{x}{| x|} = \begin{bmatrix} 0 & \frac{3}{5} & \frac{4}{5} \ \frac{2}{\sqrt{56}} & \frac{6}{\sqrt{56}} & \frac{4}{\sqrt{56}} \ \end{bmatrix}\tag{5}$$