fix: Ensure eval mode for TableReader model for predictions (#3743)

* Adding model.eval() calls to prediction functions in table reader

* Add unit test to check if model is set in train mode that inference time prediction still works.

haystack/nodes/reader/table.py

@@ -251,6 +251,7 @@ def _predict_tapas(self, inputs: BatchEncoding, document: Document) -> Answer:
         string_table = orig_table.astype(str)
 
         # Forward query and table through model and convert logits to predictions
+        self.model.eval()
         with torch.inference_mode():
             outputs = self.model(**inputs)
 
@@ -424,6 +425,7 @@ def _predict_tapas_scored(self, inputs: BatchEncoding, document: Document) -> Tu
         string_table = orig_table.astype(str)
 
         # Forward pass through model
+        self.model.eval()
         with torch.inference_mode():
             outputs = self.model.tapas(**inputs)
             table_score = self.model.classifier(outputs.pooler_output)
@@ -719,6 +721,7 @@ def predict(self, query: str, documents: List[Document], top_k: Optional[int] =
                 padding=True,
             )
             row_inputs.to(self.devices[0])
+            self.row_model.eval()
             with torch.inference_mode():
                 row_outputs = self.row_model(**row_inputs)
             row_logits = row_outputs[0].detach().cpu().numpy()[:, 1]
@@ -733,6 +736,7 @@ def predict(self, query: str, documents: List[Document], top_k: Optional[int] =
                 padding=True,
             )
             column_inputs.to(self.devices[0])
+            self.column_model.eval()
             with torch.inference_mode():
                 column_outputs = self.column_model(**column_inputs)
             column_logits = column_outputs[0].detach().cpu().numpy()[:, 1]

test/nodes/test_table_reader.py

@@ -1,6 +1,7 @@
 import logging
 
 import pandas as pd
+import torch
 import pytest
 
 from haystack.schema import Document, Answer
@@ -41,6 +42,7 @@ def table3():
 @pytest.mark.parametrize("table_reader_and_param", ["tapas_small", "rci", "tapas_scored"], indirect=True)
 def test_table_reader(table_reader_and_param, table1, table2):
     table_reader, param = table_reader_and_param
+
     query = "When was Di Caprio born?"
     prediction = table_reader.predict(
         query=query,
@@ -72,6 +74,42 @@ def test_table_reader(table_reader_and_param, table1, table2):
     assert prediction["answers"][1].offsets_in_context[0].end == reference2[param]["end"]
 
 
+@pytest.mark.parametrize("table_reader_and_param", ["tapas_small", "rci", "tapas_scored"], indirect=True)
+def test_table_reader_train_mode(table_reader_and_param, table1, table2):
+    table_reader, param = table_reader_and_param
+
+    # Set to deterministic seed
+    old_seed = torch.seed()
+    torch.manual_seed(0)
+
+    # Ensure that if model is put in train mode that predictions are not effected
+    if param != "rci":
+        table_reader.table_encoder.model.train()
+    elif param == "rci":
+        table_reader.row_model.train()
+        table_reader.column_model.train()
+
+    query = "When was Di Caprio born?"
+    prediction = table_reader.predict(
+        query=query,
+        documents=[Document(content=table1, content_type="table"), Document(content=table2, content_type="table")],
+    )
+
+    # Check the second answer in the list
+    reference2 = {
+        "tapas_small": {"answer": "5 april 1980", "start": 7, "end": 8, "score": 0.86314},
+        "rci": {"answer": "47", "start": 5, "end": 6, "score": -6.836},
+        "tapas_scored": {"answer": "brad pitt", "start": 0, "end": 1, "score": 0.49078},
+    }
+    assert prediction["answers"][1].score == pytest.approx(reference2[param]["score"], rel=1e-3)
+    assert prediction["answers"][1].answer == reference2[param]["answer"]
+    assert prediction["answers"][1].offsets_in_context[0].start == reference2[param]["start"]
+    assert prediction["answers"][1].offsets_in_context[0].end == reference2[param]["end"]
+
+    # Set back to old_seed
+    torch.manual_seed(old_seed)
+
+
 @pytest.mark.parametrize("table_reader_and_param", ["tapas_small", "rci", "tapas_scored"], indirect=True)
 def test_table_reader_batch_single_query_single_doc_list(table_reader_and_param, table1, table2):
     table_reader, param = table_reader_and_param