fix: filter and context selection (#672)

Author: shahules786

src/ragas/testset/evolutions.py

@@ -182,7 +182,7 @@ async def generate_datarow(
         assert self.generator_llm is not None, "generator_llm cannot be None"
 
         node_content = [
-            f"{i}\t{n.page_content}" for i, n in enumerate(current_nodes.nodes)
+            f"{i+1}\t{n.page_content}" for i, n in enumerate(current_nodes.nodes)
         ]
         results = await self.generator_llm.generate(
             prompt=self.find_relevent_context_prompt.format(
@@ -197,15 +197,20 @@ async def generate_datarow(
             if isinstance(relevent_contexts_result, dict)
             else None
         )
-
         if relevant_context_indices is None:
             relevant_context = CurrentNodes(
                 root_node=current_nodes.root_node, nodes=current_nodes.nodes
             )
         else:
-            selected_nodes = [current_nodes.nodes[i] for i in relevant_context_indices]
-            relevant_context = CurrentNodes(
-                root_node=selected_nodes[0], nodes=selected_nodes
+            selected_nodes = [
+                current_nodes.nodes[i - 1]
+                for i in relevant_context_indices
+                if i - 1 < len(current_nodes.nodes)
+            ]
+            relevant_context = (
+                CurrentNodes(root_node=selected_nodes[0], nodes=selected_nodes)
+                if selected_nodes
+                else current_nodes
             )
 
         merged_nodes = self.merge_nodes(relevant_context)
@@ -278,10 +283,9 @@ async def _aevolve(
         merged_node = self.merge_nodes(current_nodes)
         passed = await self.node_filter.filter(merged_node)
         if not passed["score"]:
-            nodes = self.docstore.get_random_nodes(k=1)
-            new_current_nodes = CurrentNodes(root_node=nodes[0], nodes=nodes)
+            current_nodes = self._get_new_random_node()
             return await self.aretry_evolve(
-                current_tries, new_current_nodes, update_count=False
+                current_tries, current_nodes, update_count=False
             )
 
         logger.debug("keyphrases in merged node: %s", merged_node.keyphrases)
@@ -400,7 +404,7 @@ async def _acomplex_evolution(
         )
 
         assert self.evolution_filter is not None, "evolution filter cannot be None"
-        if not await self.evolution_filter.filter(simple_question, compressed_question):
+        if await self.evolution_filter.filter(simple_question, compressed_question):
             # retry
             current_nodes = self.se._get_new_random_node()
             logger.debug(
@@ -500,7 +504,7 @@ async def _aevolve(
         )
 
         assert self.evolution_filter is not None, "evolution filter cannot be None"
-        if not await self.evolution_filter.filter(simple_question, compressed_question):
+        if await self.evolution_filter.filter(simple_question, compressed_question):
             # retry
             current_nodes = self.se._get_new_random_node()
             return await self.aretry_evolve(current_tries, current_nodes)