Error with the code in Chemical Segregation Challenge

#1

Here is the link to my code: https://drive.google.com/file/d/17Dcic8po7CFUo5ROQpKHLa1BuR2RN2Fd/view?usp=sharing

Can you please review it? Please, let me know what I am doing wrong.

#2

Hi @saurabh48782,
Replace these two lines:

w = w + learning_rate*grad_w
b = b + learning_rate*grad_b

with this:

w += learning_rate*grad_w
b += learning_rate*grad_b

This will resolve your issue. The original syntax failed to update the weights.

#3

what is the reason, both pieces of code are expected to do same thing right?

#4

The reason is pretty python specific. Some operators like “+=” modify the variables in-place, and hence, the original W array passed to the function is updated.
But, when you use it like this “W = W+x”, you are actually creating a new numpy array and assigning it to the local variable W. This fails to update the original array W passed to the function.
In the future, always use operators like “+=”, “-=”, etc. when the purpose is to modify the original array passed to the function.