How to Use MorphNet for Resource-Constrained Learning of Deep Network Structure

Aug 3, 2022 | Data Science

Welcome to the world of MorphNet! If you’re a developer looking to reduce the footprint of your convolutional neural network without sacrificing too much performance, then you’re in the right place. This guide will walk you through how to implement MorphNet and leverage its new Fine-Grained Stochastic Architecture Search (FiGS) for effective resource management.

What is MorphNet?

MorphNet is like the minimalist designer of the deep learning world. Imagine you have a fashionable outfit that is just a bit too bulky. MorphNet systematically trims down the extras while making sure that you still look good at the event. Its core principle is to learn the structure of your deep network during training by continuously adapting it. Specifically, it pushes unnecessary filters down until they are small enough to be eliminated from the overall structure.

Why Use FiGS?

FiGS takes this process a step further by introducing a probabilistic approach to channel regularization, allowing for sophisticated pruning or architecture search. Effectively, it serves as both a pruning algorithm and a full-fledged Differentiable Architecture Search method. Using FiGS is the recommended way to apply MorphNet.

Steps to Implement MorphNet

  1. Choose Your Regularizer:
    • Evaluate your target cost: FLOPs, latency, model size.
    • If adding new layers, use LogisticSigmoid regularizers (recommended).
    • If using BatchNorm, enable scale parameters by setting scale=True.
  2. Initialize the Regularizer:

    Set the threshold and boundary ops for your model. The threshold determines which output channels can be eliminated.

  3. Add Regularization Term to Your Loss:

    Determine your scaling hyperparameter by exploring a logarithmic scale.

  4. Train Your Model:

    Use a fixed learning rate to observe model structure evolution and the effects of regularization.

  5. Save Proposed Model Structure:

    Use the StructureExporter to save your model in JSON format.

  6. (Optional) Monitor Training Progress:

    Utilize summary ops to visually track updates in TensorBoard.

  7. Modify Your Model:

    Use the output from StructureExporter to finalize your model structure.

  8. Retrain Your Model (Optional):

    Retrain without MorphNet regularizer to optimize your model further.

Example Code: Adding a FLOPs Regularizer

The following code snippet demonstrates adding a FLOPs regularizer:

from morph_net.network_regularizers import flop_regularizer
from morph_net.tools import structure_exporter

def build_model(inputs, labels, is_training, ...):
    gated_relu = activation_gating.gated_relu_activation()
    net = tf.layers.conv2d(inputs, kernel=[5, 5], num_outputs=256)
    net = gated_relu(net, is_training=is_training)
    net = tf.layers.conv2d(net, kernel=[3, 3], num_outputs=1024)
    net = gated_relu(net, is_training=is_training)
    logits = tf.reduce_mean(net, [1, 2])
    logits = tf.layers.dense(logits, units=1024)
    return logits

# Prepare the network
inputs, labels = preprocessor()
logits = build_model(inputs, labels, is_training=True, ...)
network_regularizer = flop_regularizer.LogisticSigmoidFlopsRegularizer(
    output_boundary=[logits.op],
    input_boundary=[inputs.op, labels.op],
    alive_threshold=0.1)

regularization_strength = 1e-10
regularizer_loss = (network_regularizer.get_regularization_term() * regularization_strength)
model_loss = tf.nn.sparse_softmax_cross_entropy_with_logits(labels, logits)

optimizer = tf.train.MomentumOptimizer(learning_rate=0.01, momentum=0.9)
train_op = optimizer.minimize(model_loss + regularizer_loss)

In this analogy, think of each layer of your model as rooms in a mansion. The FLOPs regularizer helps to find and close off the rooms that aren’t being used, keeping the structure efficient and spacious.

Troubleshooting Tips

If you encounter issues along the way, consider the following tips:

  • Ensure your regularizer type aligns with your model architecture.
  • Check that you’ve set the threshold correctly; too high could remove important channels.
  • Verify your TensorFlow dependencies and versions to avoid compatibility problems.
  • For more insights, updates, or to collaborate on AI development projects, stay connected with fxis.ai.

Conclusion

At fxis.ai, we believe that such advancements are crucial for the future of AI, as they enable more comprehensive and effective solutions. Our team is continually exploring new methodologies to push the envelope in artificial intelligence, ensuring that our clients benefit from the latest technological innovations.

Now that you’re armed with this knowledge, dive into MorphNet and start reshaping your deep learning models for efficiency! Happy coding!

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