25. Binary cross-entropy
binary_cross_entropy()Asked in screens shaped like: OpenAI, Anthropic
Mean binary cross-entropy of labels y in {0,1} and probabilities p in (0,1), rounded to 4 decimals. Use natural log.
Examples
Example 1
Input: { "y": [1, 0], "p": [0.9, 0.1] } Output: 0.1054
Constraints
- p is in (0, 1); y is 0 or 1
Implement binary_cross_entropy(). Types below are the NumPy contract; Python and PyTorch use lists or tensors with the same names.
| Name | Type | I/O |
|---|---|---|
| y | array | Input |
| p | array | Input |
| value | float | Output |
Same tests, three APIs. Pick a language with the chips above the editor.
NumPy
Vectorized arrays. Default for analyst, scientist, and DE screens.
Revealed one at a time. The reference implementation stays in the Solution tab.
Hint 1
Keep the function signature. Fill the body — do not rename parameters.
Hint 2
Match the rounding in the examples. Tests compare with a small numeric tolerance.
Hint 3
Switch NumPy / Python / PyTorch with the chips above the editor. Each language has its own tests.
Run your code to see stdout.
Submit to run the checks.
All tests passed on this language.
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