pytorch type_error ai_generated true

RuntimeError: TorchScript supports tracing only for tensors. This function cannot be traced because it uses dynamic control flow (if/else or loops) that depends on tensor data.

ID: pytorch/torchscript-unsupported-dynamic-control-flow

Also available as: JSON · Markdown · 中文
90%Fix Rate
90%Confidence
1Evidence
2024-04-10First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
pytorch>=1.8.0 active — — —

Root Cause

The model contains control flow (e.g., if x.sum() > 0) that depends on tensor values, which is not supported by torch.jit.trace; torch.jit.script is required instead.

generic

中文

模型包含依赖于张量值的控制流（如 if x.sum() > 0），torch.jit.trace 不支持；需要使用 torch.jit.script。

Official Documentation

https://pytorch.org/docs/stable/jit.html#mixing-tracing-and-scripting

Workarounds

  1. 95% success Replace torch.jit.trace with torch.jit.script for the entire model or the specific module with control flow. Script supports dynamic control flow. 
    Replace torch.jit.trace with torch.jit.script for the entire model or the specific module with control flow. Script supports dynamic control flow.
  2. 85% success If you must use tracing, refactor the control flow into a separate function and use torch.jit.script for that function, then call it from the traced module. 
    If you must use tracing, refactor the control flow into a separate function and use torch.jit.script for that function, then call it from the traced module.

中文步骤

  1. 将 torch.jit.trace 替换为 torch.jit.script 用于整个模型或包含控制流的特定模块。Script 支持动态控制流。
  2. 如果必须使用 tracing，将控制流重构到单独的函数中，并使用 torch.jit.script 处理该函数，然后从 traced 模块中调用它。

Dead Ends

Common approaches that don't work:

  1. 90% fail

    Tracing captures the operations executed for given inputs; it cannot handle branches not taken.

  2. 70% fail

    Ignoring the function means it won't be compiled, leading to missing operations in the exported graph.

  3. 50% fail

    Removing control flow changes model logic; it may work but is error-prone and not always feasible.