Slides explaining thatsfordinner.com, a fast recipe browser for maximal inspiration in minimal time. Uses latent Dirichlet allocation (LDA) to group recipes with shared ingredients.

1. Fast recipe browsing for maximal inspiration
Thatsfordinner.com
Alexander Jerneck

2. Demo

3. Data
● 16K recipes scraped from epicurious.com and allrecipes.com.
● Ingredient and title words are the features.
● Typical NLP preprocessing and feature selection.
● Vocabulary size: about 1800 words.

4. Algorithm: Topic model (Latent Dirichlet Allocation)
Potatoes 0.7
Russet 0.1
Gold 0.1
Yukon 0.1
Chili 0.4
Cilantro 0.4
Avocado 0.2
Ginger 0.4
Rice 0.3
Soy 0.3
● Documents are mixtures of topics and words in documents are drawn
from topics:
○ 1 tsp soy sauce, 1 cup rice, 1 piece ginger, 1 chili pepper
○ 3 pounds russet potatoes, 3 pounds Yukon Gold potatoes, 1 stick butter, 1 cup whole
milk, salt
○ 1 avocado, 1 tbsp cilantro, 2 tbsp onion, 1 chili pepper

5. How many
topics?

6. Validation:
Stability

7. Alexander Jerneck
● Programming enthusiast living inside a social scientist (Ph.D., Sociology).
● I did this project because
○ I want to be able to read everything.
○ I want to make people find new things they didn’t know they wanted.

9. LDA: Generative process
1. For each topic,
a. Draw a distribution over words βk
∼ DirV
(η).
2. For each document,
a. Draw a vector of topic proportions θd
∼ Dir (α).
b. For each word,
i. Draw a topic assignment Zd,n
∼ Mult(θd
), Zd,n
∈ {1,..., K}.
ii. Draw a word Wd,n
∼ Mult(βzd,n
),Wd,n
∈{1,...,V}
V is the size of the vocabulary.
K is the number of topics.
η and α are hyperparameters determining the shape of the Dirichlet distributions.
.

10. LDA: Inference
The posterior:
p(θ1:D
,z1:D,1:N
,β1:K
|w1:D,1:N
,α,η) = p(θ1:D
,z1:D
,β1:K
|w1:D
,α,η)/
∫β1:K
∫θ1:D
∑z
p(θ1:D
,z1:D
,β1:K
|w1:D
,α,η)
is intractable because of the integral in the denominator.
I use collapsed Gibbs sampling, implemented in the python lda package to sample from the
posterior.

11. Landing page: all categories

12. Category detail view

13. All recipes in a category

14. Search for lemon + butter in a category