Neural Network Compression: Difference between revisions

 
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Brief survey on neural network compression techniques consisting of popular papers I pull from existing surveys.
Brief survey on neural network compression techniques sampled from existing surveys.


==Pruning==
==Pruning==
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# Compute sensitivity for each parameter.
# Compute sensitivity for each parameter.
# Delete low-saliency parameters.
# Delete low-saliency parameters.
# Continue training and repeat pruning until the number of parameters is low enough or error is too high.
# Continue training to fine-tune remaining parameters.
# Repeat pruning until the number of parameters is low enough or the error is too high.


Sometimes, pruning can also increase accuracy and improve generalization.
Sometimes, pruning can also increase accuracy and improve generalization.
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* Mozer and Smolensky (1988)<ref name="mozer1988skeletonization"></ref> use a gate for each neuron. Then the sensitivity and be estimated with the derivative w.r.t the gate.
* Mozer and Smolensky (1988)<ref name="mozer1988skeletonization"></ref> use a gate for each neuron. Then the sensitivity and be estimated with the derivative w.r.t the gate.
* Karnin<ref name="karnin1990simple"></ref> estimates the sensitivity by monitoring the change in weight during training.
* Karnin<ref name="karnin1990simple"></ref> estimates the sensitivity by monitoring the change in weight during training.
* LeCun ''e al.'' present ''Optimal Brain Damage'' <ref name="lecun1989optimal"></ref> which uses the
* LeCun ''e al.'' present ''Optimal Brain Damage'' <ref name="lecun1989optimal"></ref> which uses the second derivative of each weight.


===Redundancy Methods===
===Redundancy Methods===
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===Structured Pruning===
===Structured Pruning===
Structured pruning focuses on keeping the dense structure of the network such that the pruned weights can benefit using standard dense matrix multiplication operations.
Structured pruning focuses on keeping the dense structure of the network such that the pruned network can benefit using standard dense matrix multiplication operations.<br>
This is in contrast to unstructured pruning which zeros out values in the weight matrix but may not necessarilly run faster.


* Wen ''et al.'' (2016) <ref name="wen2016learning"></ref> propose Structured Sparsity Learning (SSL) on CNNs. Given filters of size (N, C, M, K), i.e. (out-channels, in-channels, height, width), they use a group lasso loss/regularization to penalize usage of extra input and output channels. They also learn filter shapes using this regularization.
* Wen ''et al.'' (2016) <ref name="wen2016learning"></ref> propose Structured Sparsity Learning (SSL) on CNNs. Given filters of size (N, C, M, K), i.e. (out-channels, in-channels, height, width), they use a group lasso loss/regularization to penalize usage of extra input and output channels. They also learn filter shapes using this regularization.