Add multilingual MATH-500 (mmath500) task

src/lighteval/tasks/multilingual/tasks/mmath500.py

@@ -0,0 +1,108 @@
+"""
+name:
+mMATH-500
+
+dataset:
+LumiOpen/MATH-500_mt
+
+abstract:
+Multilingual translations of the MATH-500 benchmark, a subset of 500 problems
+from the MATH benchmark that OpenAI created in their Let's Verify Step by Step
+paper. Currently contains Finnish translations produced with Claude Opus 4.5.
+
+languages:
+finnish
+
+tags:
+math, reasoning, multilingual
+
+paper:
+https://arxiv.org/abs/2305.20050
+"""
+
+import os
+
+from inspect_ai.dataset import Sample
+from inspect_ai.model import GenerateConfig, get_model
+from inspect_ai.scorer import model_graded_fact
+from inspect_ai.solver import generate, prompt_template
+
+from lighteval.metrics.metrics import Metrics
+from lighteval.tasks.lighteval_task import LightevalTaskConfig
+from lighteval.tasks.requests import Doc
+
+
+MATH_QUERY_TEMPLATES = {
+    "fi": """
+Ratkaise seuraava tehtävä. Vastauksesi viimeisen rivin TÄYTYY olla seuraavassa muodossa:
+"ANSWER: $ANSWER" (ilman lainausmerkkejä), jossa $ANSWER on lopullinen vastaus. Ajattele vaiheittain ennen vastaamista.
+
+{prompt}
+""".strip(),
+}
+
+
+def _get_scorer_model():
+    """Resolve the scorer model from environment variables if available.
+
+    When SCORER_MODEL_BASE_URL is set (e.g. by the eval harness which starts
+    a dedicated scorer vLLM server), connect to it via the OpenAI-compatible
+    API. Otherwise return None so model_graded_fact uses the eval model.
+    """
+    base_url = os.environ.get("SCORER_MODEL_BASE_URL")
+    if base_url:
+        model_name = os.environ.get("SCORER_MODEL_PATH", "Qwen/Qwen3.5-9B")
+        return get_model(
+            f"openai-api/scorer/{model_name}",
+            config=GenerateConfig(
+                extra_body={"chat_template_kwargs": {"enable_thinking": False}},
+            ),
+            base_url=base_url,
+            api_key=os.environ.get("VLLM_API_KEY", "inspectai"),
+        )
+    return None
+
+
+def _mmath500_prompt_fn(lang: str):
+    template = MATH_QUERY_TEMPLATES[lang]
+
+    def mmath500_prompt(line, task_name: str = None):
+        query = template.format(prompt=line["problem"])
+        return Doc(
+            task_name=task_name,
+            query=query,
+            choices=[f"ANSWER: {line['answer']}"],
+            gold_index=0,
+        )
+
+    return mmath500_prompt
+
+
+def record_to_sample(record):
+    query = record["problem"]
+    target = record["answer"]
+    return Sample(input=query, target=target)
+
+
+mmath500_fi = LightevalTaskConfig(
+    name="mmath500:fi",
+    prompt_function=_mmath500_prompt_fn("fi"),
+    hf_repo="LumiOpen/MATH-500_mt",
+    hf_subset="default",
+    hf_avail_splits=["fi"],
+    evaluation_splits=["fi"],
+    few_shots_split=None,
+    few_shots_select=None,
+    generation_size=32768,
+    metrics=[
+        Metrics.pass_at_k_math(sample_params={"k": 1, "n": 1}),
+    ],
+    version=1,
+    sample_fields=record_to_sample,
+    solver=[prompt_template(MATH_QUERY_TEMPLATES["fi"]), generate(cache=True)],
+    scorer=model_graded_fact(model=_get_scorer_model()),
+)
+
+TASKS_TABLE = [
+    mmath500_fi,
+]