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Optimize tensor operation chains

comfyanonymous/ComfyUI
Based on 2 comments
Python

When working with PyTorch tensors, look for opportunities to optimize operation chains for better performance and memory efficiency. This involves two key strategies:

Pytorch Python

Reviewer Prompt

When working with PyTorch tensors, look for opportunities to optimize operation chains for better performance and memory efficiency. This involves two key strategies:

  1. Use inplace operations when safe: For non-leaf tensors, inplace operations (+=, *=, etc.) can reduce memory allocation and improve performance. Check if a tensor is a leaf node before deciding:
def optimized_add(x: torch.Tensor, value: float) -> torch.Tensor:
    if x.is_leaf:
        x = x + value  # Create new tensor for leaf nodes
    else:
        x += value     # Inplace operation for non-leaf nodes
    return x
  1. Mathematically simplify operation chains: Look for algebraically equivalent expressions that require fewer operations:
# Instead of: x.add(1.0).div(2.0).clamp(0,1).mul(255.).round()
# Use: x.add(1.0).clamp(0,2).mul(127.5).round()
# This eliminates one operation while maintaining mathematical correctness

These optimizations are particularly important in neural network forward/backward passes where tensor operations are performed repeatedly on large data. Always verify mathematical equivalence when simplifying operation chains, and profile performance gains in your specific use case.

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Python
Primary Language
Pytorch
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