Chap15 conv1d and conv2d

[JohannWO]

When running the naive Implementation of conv1d and conv2d with example in book then it shows wrong results.

conv1d works for
X = [[1, 3, 2, 4], [5, 6, 1, 3], [1, 2, 0, 2], [3, 4, 3, 2]]
W = [[1, 0, 3], [1, 2, 1], [0, 1, 1]]
Conv1d Implementation p=2 s=1: [ 5. 14. 16. 26. 24. 34. 19. 22.] <- Correct

conv1d for (German Book, 2. Auflage, Seite 493)
x= [3, 2, 1, 7, 1, 2, 5, 4]
w= [0.5, 0.75, 1.0, 0.25]
Conv1d Implementation p=0 s=2: [7. 9.] <- Wrong
Expected: [7 9 8]

conv2d works for
X= [[1, 3, 2, 4], [5, 6, 1, 3], [1, 2, 0, 2], [3, 4, 3, 2]]
W= [[1, 0, 3], [1, 2, 1], [0, 1, 1]]
Correct Result

conv2d for (German Book, 2. Auflage, Seite 498)
X= [[2, 1, 2], [5, 0, 1], [1, 7, 3]]
W= [[0.5, 0.7, 0.4], [0.3, 0.4, 0.1], [0.5, 1.0, 0.5]]
Conv2d Implementation p=1,1 s=2,2: [[4.6]]
Expected: [[4.6, 1.6], [7.5, 2.9]

Even if both implementations are called naive, they should return correct results.
I think the problem is the end-condition in the for-statement.

conv1d
book: for j in range(0, int(len(x)/s), s):
new: for j in range(0, len(x_padded)-len(w_rot)+1, s):

conv2d
book:
for i in range(0, int((X_padded.shape[0] - W_rot.shape[0]) / s[0]) + 1, s[0]): # Fehler bei s=2,2
for j in range(0, int((X_padded.shape[1] - W_rot.shape[1]) / s[1]) + 1, s[1]): # Fehler bei s=2,2
new:
for i in range(0, int((X_padded.shape[0] - W_rot.shape[0]) ) + 1, s[0]):
for j in range(0, int((X_padded.shape[1] - W_rot.shape[1]) ) + 1, s[1]):

[rasbt]

Thanks for the note. It's been a few years ago, but I vaguely remember this issue. I believe we had fixed that in the 3rd edition: https://github.com/rasbt/python-machine-learning-book-3rd-edition/blob/master/ch15/ch15_part1.ipynb

[JohannWO]

Had a look at the Jupyter Notebook of 3rd Edition
conv1d:
the code was changed to
3rd edition: for i in range(0, int((len(x_padded) - len(w_rot)) / s) + 1, s):
when you use this code with example in Out[5] it returns the wrong result: Conv1d Implementation p=0 s=2: [7. 9.]
i think the "/ s" is wrong, as you take s as step

conv2d:
the code was not changed.
example in Out[11] still results in [[4.6]]

I only compared the for-statements. If there were further changes in the code, i did not check this.

[rasbt]

You are right. Arg, yeah, the /s shouldn't be there. Probably didn't notice due to setting s=1. Need to check this more thoroughly and update it. I will add a reference on the 3rd editions issue tracker so that it can be fixed in the 4th edition.