The Lottery Ticket Hypothesis Finding Sparse, Trainable Neural Networks

Tags: paper ml
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Code: None
  • Pruning can reduce network by 90% without compromising accuracy
  • Standard pruning naturally uncovers sub-networks whose initialization made them capable of training effectively
  • They find "winning tickets" consistently for MNSIT and CIFAR10


  • $$f(x, \theta)$$ is some dense FF network where $$\theta_0 \sim D_\theta$$ for some distribution of parameters $$D_\theta$$
  • $$f$$ reaches $$l$$ validation loss and test accuracy $$a$$ at some iteration $$j$$ from e.g. SGD
  • Consider training $$f(x, m \dot \theta)$$ for some fixed mask $$m \in {0, 1}^{\Vert{\theta}\Vert}$$
    • This will reach some validation loss $l'$, at iteration $j'$ for some test accuracy $a'$
  • LTH States: $$\exists M$$ where $j' \leq j$, $a' \leq a$

To find such $M$ they propose an algorithm:

  1. Randomly initialize $f(x, \theta_0)$
  2. Train for some fixed iterations
  3. Prune p% of the network, to construct the mask $M$
  4. Reset the parameters to $\theta_0$ and retrain the model

Repeat this procedure iteratively over n rounds, combining the mask over each round. They should empirically that this out-performs doing this once.

They have experimental results on MNIST and CIFAR10