I attempted to execute the following SQL statement to train using the passive_aggressive algorithm:
SELECT * FROM pgml.train('Iris Flower Types', 'classification', 'pgml.iris_view', 'target', 'passive_aggressive');

However, after executing this SQL statement multiple times, I encountered an error with the algorithm. The error message is as follows:
ERROR: called Option::unwrap() on a None value

On the other hand, other algorithms such as SVM and linear regression do not have this issue. I'm unsure if this error is due to a limitation of the algorithm itself or if there are other underlying issues causing it.

Here is the complete replication process:
SELECT * FROM pgml.load_dataset('iris'); # OK
DROP VIEW IF EXISTS pgml.iris_view; # OK
CREATE VIEW pgml.iris_view AS SELECT * FROM pgml.iris ORDER BY random() LIMIT 100; # OK
SELECT * FROM pgml.train('Iris Flower Types', 'classification', 'pgml.iris_view', 'target', 'passive_aggressive'); # OK, deployed is t
SELECT * FROM pgml.train('Iris Flower Types', 'classification', 'pgml.iris_view', 'target', 'passive_aggressive'); # OK, deployed is t
SELECT * FROM pgml.train('Iris Flower Types', 'classification', 'pgml.iris_view', 'target', 'passive_aggressive'); # ERROR: called Option::unwrap() on a None value
SELECT * FROM pgml.train('Iris Flower Types', 'classification', 'pgml.iris_view', 'target', 'passive_aggressive'); # OK, deployed is f
SELECT * FROM pgml.train('Iris Flower Types', 'classification', 'pgml.iris_view', 'target', 'svm'); # OK
SELECT * FROM pgml.train('Iris Flower Types', 'classification', 'pgml.iris_view', 'target', 'svm'); # OK
SELECT * FROM pgml.train('Iris Flower Types', 'classification', 'pgml.iris_view', 'target', 'svm'); # OK
SELECT * FROM pgml.train('Iris Flower Types', 'classification', 'pgml.iris_view', 'target', 'svm'); # OK
SELECT * FROM pgml.train('Iris Flower Types', 'classification', 'pgml.iris_view', 'target', 'svm'); # OK

By the way, my execution environment is
sudo docker run --rm -it -v postgresml_data:/var/lib/postgresql -p 5434:5432 -p 8000:8000 ghcr.io/postgresml/postgresml:2.8.1 sudo -u postgresml psql -d postgresml