# Ground Truth Encoder

The ground truth encoder generates a ground truth value correlated with a sample, with index `idx`, from the `preprocess`. It will later be used as the ground truth for the **loss** function. This function is called for each evaluated sample.

For example:

```python
from code_loader.contract.datasetclasses import PreprocessResponse
from code_loader.inner_leap_binder.leapbinder_decorators import tensorleap_gt_encoder

@tensorleap_gt_encoder(name='classes')
def gt_encoder(idx: int, preprocess: Union[PreprocessResponse, list]) -> np.ndarray:
    return preprocess.data.iloc[idx]['ground_truth'].astype('float32')
```

The [@tensorleap\_gt\_encoder](/tensorleap-integration/python-api/code_loader/decorators/tensorleap_gt_encoder.md) decorator registers each gt encoder into the Tensorleap integration.

Usage within the full script can be found at the [**Dataset Script**](/tensorleap-integration/writing-integration-code.md#dataset-script).


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