What is a loss function?

Updated May 17, 2026

Short answer

A loss function measures the difference between predicted and actual values.

Deep explanation

It quantifies model error. Common loss functions include MSE for regression and cross-entropy for classification.

Real-world example

Used in training image classifiers.

Common mistakes

  • Choosing wrong loss function for the task.

Follow-up questions

  • What is cross entropy loss?
  • Why not use MSE for classification?

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