[BUG] The multi-stage example is broken due to recent changes in systems

[rnyak]

Bug description

We are getting the error below due to some changes in faiss op in Systems from this unit test:

E               testbook.exceptions.TestbookRuntimeError: An error occurred while executing the following cell:
E               ------------------
E               from merlin.systems.dag.ops.faiss import QueryFaiss, setup_faiss 
E               
E               item_embeddings = np.ascontiguousarray(
E                   pd.read_parquet(os.path.join(BASE_DIR, "item_embeddings.parquet")).to_numpy()
E               )
E               setup_faiss(item_embeddings, faiss_index_path)
E               ------------------
E               
E               
E               ---------------------------------------------------------------------------
E               IndexError                                Traceback (most recent call last)
E               Cell In[10], line 6
E                     1 from merlin.systems.dag.ops.faiss import QueryFaiss, setup_faiss 
E                     3 item_embeddings = np.ascontiguousarray(
E                     4     pd.read_parquet(os.path.join(BASE_DIR, "item_embeddings.parquet")).to_numpy()
E                     5 )
E               ----> 6 setup_faiss(item_embeddings, faiss_index_path)
E               
E               File /usr/local/lib/python3.8/dist-packages/merlin/systems/dag/ops/faiss.py:209, in setup_faiss(item_vector, output_path, metric, item_id_column, embedding_column)
E                   192 def setup_faiss(
E                   193     item_vector: DataFrameLike,
E                   194     output_path: str,
E                  (...)
E                   197     embedding_column="embedding",
E                   198 ):
E                   199     """
E                   200     Utiltiy function that will create a Faiss index from a set of embedding vectors
E                   201 
E                  (...)
E                   207         target output path
E                   208     """
E               --> 209     ids = item_vector[item_id_column].to_numpy().astype(np.int64)
E                   210     item_vectors = np.ascontiguousarray(
E                   211         np.stack(item_vector[embedding_column].to_numpy()).astype(np.float32)
E                   212     )
E                   214     index = faiss.index_factory(item_vectors.shape[1], "IVF32,Flat", metric)
E               
E               IndexError: only integers, slices (`:`), ellipsis (`...`), numpy.newaxis (`None`) and integer or boolean arrays are valid indices

/usr/local/lib/python3.8/dist-packages/testbook/client.py:135: TestbookRuntimeError

Steps/Code to reproduce bug

You can run this unit test to repro the error.

Expected behavior

Environment details

• Merlin version:
• Platform:
• Python version:
• PyTorch version (GPU?):
• Tensorflow version (GPU?):

Additional context

There is an open PR in Merlin to update the building_deploying_multi_stage_RecSys example, hopefully that might address this issue.

[karlhigley]

@rnyak The change that led to this failure was motivated by the updates to the multi-stage notebook, and #1022 contains corresponding updates to make use of the changes to setup_faiss