mscdit
Programming Machine Learning - Dimension numbers correct? (page 118)
Hi @nusco,
I have a question regarding the dimension numbers of the matrices shown in the picture on page 118. What I am currently struggling with is, node “h_0” is used for bias purpose (which means constant value 1). So if weight vector w_1 has 201 columns, this implies that all hidden nodes h_0, h_1, … h_200 are calculated via w_1 … but looking in the code-snipets on page 122,
h = sigmoid(np.matmul(prepend_bias(X), w1))
vector h should have 202 entries, if w1 has 201, which doesn’t fit into the picture of page 118, or?
Thanks a lot,
Mscdit
First Post!
nusco
Here I am, at long last! Sorry for the slow reply, @mscdit . I was knocked out by the flu.
This looks indeed like a mistake in that diagram (that is even repeated in two consecutive chapters). w1 should be (785, 200), not (785, 201). Then the hidden layer is (M, 200), and it becomes (M, 201) when you prepend the biases.
Thank you for spotting it! I’ll add to the errata for future editions.
Popular Pragmatic Bookshelf topics
Other popular topics
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /wasm
- /ruby
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /java
- /emacs
- /haskell
- /svelte
- /onivim
- /typescript
- /kotlin
- /c-plus-plus
- /crystal
- /tailwind
- /react
- /gleam
- /ocaml
- /flutter
- /elm
- /vscode
- /ash
- /html
- /opensuse
- /zig
- /deepseek
- /centos
- /php
- /scala
- /react-native
- /lisp
- /textmate
- /sublime-text
- /nixos
- /debian
- /agda
- /django
- /deno
- /kubuntu
- /arch-linux
- /nodejs
- /revery
- /ubuntu
- /manjaro
- /spring
- /julia
- /lua
- /diversity
- /markdown
- /slackware
Devtalk Sponsors
Practical resources that improve the lives of professional developers.
We build trusted fault-tolerant systems that scale to billions of users.
Real-time error tracking, performance insights, and observability for devs.
Supporting innovation across the BEAM ecosystem.
We build reliable cloud platforms for business-critical systems.
Develop your skills with books, videos, and courses.
Catch errors, track performance, monitor hosts and more.
Enabling companies to succeed by building software people love.
Courses that move you from confusion to "Aha, now I get it!"
Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.