Implement FixedFewShotGenerator

flexeval/core/few_shot_generator/__init__.py

@@ -1,3 +1,4 @@
 from .balanced import BalancedFewShotGenerator
 from .base import FewShotGenerator
+from .fixed import FixedFewShotGenerator
 from .rand import RandomFewShotGenerator

flexeval/core/few_shot_generator/fixed.py

@@ -0,0 +1,28 @@
+from __future__ import annotations
+
+from typing import Any
+
+from .base import ChatInstance, FewShotGenerator, GenerationInstance, Instance, MultipleChoiceInstance
+
+
+class FixedFewShotGenerator(FewShotGenerator):
+    def __init__(self, instance_class: str, instance_params: list[dict[str, Any]]) -> None:
+        super().__init__(num_trials_to_avoid_leak=0)
+
+        if instance_class == "GenerationInstance":
+            instance_init = GenerationInstance
+        elif instance_class == "MultipleChoiceInstance":
+            instance_init = MultipleChoiceInstance
+        elif instance_class == "ChatInstance":
+            instance_init = ChatInstance
+        else:
+            msg = f"Unknown instance class: {instance_class}"
+            raise ValueError(msg)
+
+        self.instances = [instance_init(**params) for params in instance_params]
+
+    def _sample_instances(self, eval_inputs: list[dict[str, Any]] | dict[str, Any] | None = None) -> list[Instance]:
+        return self.instances
+
+    def __repr__(self) -> str:
+        return f"{self.__class__.__name__}(instances={self.instances})"

tests/core/few_show_generator/test_fixed.py

@@ -0,0 +1,13 @@
+from flexeval import ChatInstance
+from flexeval.core.few_shot_generator.fixed import FixedFewShotGenerator
+
+
+def test_fixed_fewshot_generator() -> None:
+    instance = ChatInstance(
+        messages=[{"role": "user", "content": "Hello!"}, {"role": "assistant", "content": "Hi there!"}]
+    )
+    generator = FixedFewShotGenerator(
+        instance_class="ChatInstance",
+        instance_params=[{"messages": instance.messages} for _ in range(5)],
+    )
+    assert generator() == [instance for _ in range(5)]