bigfunctions > precision_recall_auc
precision_recall_auc¶
Signature
precision_recall_auc(predictions)
Description
Returns the Area Under the Precision Recall Curve (a.k.a. AUC PR) given a set of predicted scores and ground truth labels using the trapezoidal rule
Examples
1. Random classifier
select bigfunctions.eu.precision_recall_auc((select array_agg(struct(cast(predicted_score as float64), rand() > 0.5)) from unnest(generate_array(1, 1000)) as predicted_score))
select bigfunctions.us.precision_recall_auc((select array_agg(struct(cast(predicted_score as float64), rand() > 0.5)) from unnest(generate_array(1, 1000)) as predicted_score))
select bigfunctions.europe_west1.precision_recall_auc((select array_agg(struct(cast(predicted_score as float64), rand() > 0.5)) from unnest(generate_array(1, 1000)) as predicted_score))
+--------+
| auc_pr |
+--------+
| 0.5 |
+--------+
2. Good classifier
select bigfunctions.eu.precision_recall_auc((select array_agg(struct(cast(predicted_score as float64), predicted_score > 500)) from unnest(generate_array(1, 1000)) as predicted_score))
select bigfunctions.us.precision_recall_auc((select array_agg(struct(cast(predicted_score as float64), predicted_score > 500)) from unnest(generate_array(1, 1000)) as predicted_score))
select bigfunctions.europe_west1.precision_recall_auc((select array_agg(struct(cast(predicted_score as float64), predicted_score > 500)) from unnest(generate_array(1, 1000)) as predicted_score))
+--------+
| auc_pr |
+--------+
| 1.0 |
+--------+