Sample code for chapter 9

Page 185 of the book/pdf.

Updated:
To calculate the impact of the example weight, w0, on the output

With:
To calculate the impact of the example input, x0, on the output

All of the other places mention x0, input, and not w0, weight

Multiple pages in this chapter:

Updated:
# Partial derivatives of the multiplication, the chain rule

With:
# Partial derivatives of the sum, the chain rule

The comment said multiplication, when it's sum and confuses people

Book page 213:

Updated:

                    # Layer initialization
                    def __init__(self, inputs, neurons):
                        self.weights = 0.01 * np.random.randn(inputs, neurons)
                        self.biases = np.zeros((1, neurons))
                

With:

                    # Layer initialization
                    def __init__(self, n_inputs, n_neurons):
                        # Initialize weights and biases
                        self.weights = 0.01 * np.random.randn(n_inputs, n_neurons)
                        self.biases = np.zeros((1, n_neurons))

The important part is not the comment (which also was missing), but missing n_ in variable names which we have added everywhere else

Chapter 9, page 223:

Updated:
The difference is that now the whole subtrahend solves to 0, leaving us with just the minuend in the numerator:

With:
The difference is that now the whole minuend solves to 0, leaving us with just the subtrahend in the numerator:

subtrahend and minuend were swapped (incorrectly used)