Debugging Disconnected Gradients in TensorFlow Step by Step

This article explains why TensorFlow’s tf.GradientTape sometimes returns None when computing gradients. It explores common pitfalls such as disconnected variables, non-TensorFlow operations, integer or string data types, and stateful objects that block gradient flow. The guide also covers cases where gradients aren’t registered for specific TensorFlow operations and how to handle unconnected gradients by returning zeros instead of None. Practical examples illustrate how to diagnose and resolve these issues when training or debugging deep learning models.