add mgsm

lm_eval/tasks/llama3/instruct/mgsm_chat.yaml

+tag: llama3
+task: mgsm_chat
+dataset_path: meta-llama/Llama-3.2-3B-Instruct-evals
+dataset_name: Llama-3.2-3B-Instruct-evals__mgsm__details
+output_type: generate_until
+test_split: latest
+doc_to_text: "{{
+    input_final_prompts
+    |first
+    |replace('<|eot_id|><|start_header_id|>assistant<|end_header_id|>', '')
+    |replace('<|start_header_id|>', '')
+    |replace('<|end_header_id|>', '')
+    |replace('<|eot_id|>', '')
+    |replace('^user', '')
+    |trim
+}}"
+doc_to_target: "input_correct_responses"
+process_results: !function utils.process_results_mgsm
+generation_kwargs:
+  until: []
+  do_sample: false
+  temperature: 0.0
+  max_gen_toks: 2048
+metric_list:
+  - metric: exact_match
+    aggregation: mean
+    higher_is_better: true
+    ignore_case: true
+    ignore_punctuation: true
+filter_list:
+  - name: "strict-match"
+    filter:
+      - function: "regex"
+        regex_pattern: "Answer: (\\-?[0-9\\.\\,]+)"
+      - function: "take_first"
+  - name: "flexible-extract"
+    filter:
+      - function: regex
+        group_select: -1
+        regex_pattern: "Answer: (-?[$0-9.,]{2,})|(-?[0-9]+)"
+      - function: take_first
+      - function: remove_whitespace
+      - function: take_first
+metadata:
+  version: 0.0

lm_eval/tasks/llama3/instruct/utils.py

+from typing import List
+
+from lm_eval.api.metrics import exact_match_fn
+
+
+def process_results_mgsm(doc, prediction):
+    gold: List = doc["input_correct_responses"]
+    return {
+        "exact_match": int(
+            exact_match_fn(
+                predictions=prediction * len(gold), references=gold, ignore_case=True
+            )["exact_match"]
+            > 0
+        )
+    }