This article is about how I tested a hypothesis I had by building a website in 3 days. It’s not my first time building something to test business hypothesis but this time I wanted to do it faster and document the processes.

Hypothesis

The hypothesis is that people enjoy commenting 💩…

fastai/course-v4

fastai/fastbook

High school math is enough to understand deep learning.

Lots of data is not needed but some record-breaking results have been made with <50 items.

You don’t need an expensive computer but start of the art results can be made for free.

Deep learning is the same as…

fastai/fastbook

Language model = a model that tries to predict the next word of a sentence.

A language model works well on transfer learning as the base model because it knows something about language as it can predict the next word of a sentence.

The base language model should be…

fastai/fastbook

Weight decay (L2 regularization)

The idea is to add the sum of all the weights squared to the loss function. This way the model tries to keep the weights as small as possible because bigger weights will increase the final loss.

loss_with_wd = loss + wd * (parameters**2).sum()

It’s…

fastai/fastbook

learn = cnn_learner(dls, resnet34, metrics=error_rate)
learn.fine_tune(2, base_lr=0.1)

Learning rate finder helps to pick the best learning rate. The idea is to change the learning rate after every mini-batch and then plot the loss. Good learning rate is somewhere between the steepest point and the minimum. So for example based…

fastai/fastbook

Create dataset

train_x = torch.cat([stacked_threes, stacked_sevens]).view(-1, 28*28)
train_y = tensor([1] * len(threes) + [0] * len(sevens)).unsqueeze(1)
print(train_x.shape, train_y.shape)
CONSOLE: (torch.Size([12396, 784]), torch.Size([12396, 1]))
dset = list(zip(train_x, train_y))
x, y = dset[0]
print(x.shape, y)
PRINT: (torch.Size([784]), tensor([1]))

Create weights

def init_params(size, variance=1.0):
    return (torch.randn(size)*variance).requires_grad_()weights = init_params((28*28,1))
bias = init_params(1)…

fastai/fastbook

# Load saved learner
learn_inf = load_learner(path/'export.pkl')
# Predict given image
learn_inf.predict('images/grizzly.jpg')
# See labels
learn_inf.dls.vocab

Jupyter Notebook widgets are created using IPython widgets.

Deploying CPU is easier than GPU in most of the cases. GPU is needed only if the deployed model still requires a lot of computation…

fastai/fastbook

Classification = Predict label (e.g. dog or cat)

Regression = Predict number (e.g. how old)

The last time we looked this code:

valid_pct=0.2 (validation percent) means that the loader is going to put 20% of the given data aside in training. Then this data is used to measure how…