llsourcell/how_to_do_math_for_deep_learning

This is the code for "How to Do Math Easily - Intro to Deep Learning #4' by Siraj Raval on YouTube

how_to_do_math_for_deep_learning's Issues

Error in forward prop

In line 28, what is written is:
k0 = X

It should be:
k0 = nonlin(X)

this is so that the weights are effected by the output of the node and not the input, and would also be consistent with the k1 and k2 values used.

Syntax Error in demo.ipynb

When I run the Jupiter notebook, line 14 will not display unless the variable is in parentheses. Anyone else encountering this?

Syntax error in python3.

anyone knows what's the exact problem here?
it's giving me a syntax error in python3

-----k2_delta = k2_error * nonlin(k2,deriv=True)
------------^
SyntaxError: invalid syntax

Can you explain the last two lines where the gradients are being updated?

syn1 += k1.T.dot(k2_delta) syn0 += k0.T.dot(k1_delta)
Could you explain a little more in depth the thought process behind these lines? Came here from the video and still confused. How does k1.dot k2_delta create the amount to update the weight? I understand the gradient is the direction we need to travel but wouldn't we just subtract that distance from the weight? Why do we need to dot product?

Thanks!