[Config] Refactor mistral configs (#20570)

Signed-off-by: Patrick von Platen <patrick.v.platen@gmail.com>

vllm/transformers_utils/configs/mistral.py

@@ -0,0 +1,120 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+from typing import Any
+
+from transformers import PretrainedConfig
+
+from vllm.logger import init_logger
+
+logger = init_logger(__name__)
+
+
+def adapt_config_dict(config_dict: dict[str, Any],
+                      **kwargs) -> PretrainedConfig:
+    config_dict.update(kwargs)
+    config_dict = _remap_general_mistral_args(config_dict)
+
+    if bool(config_dict.get("quantization")):
+        config_dict = _remap_mistral_quantization_args(config_dict)
+
+    if bool(config_dict.get("moe")):
+        config_dict["architectures"] = ["MixtralForCausalLM"]
+    else:
+        config_dict["architectures"] = ["MistralForCausalLM"]
+
+    if bool(config_dict.get("yarn")):
+        config_dict = _remap_mistral_yarn_args(config_dict)
+    if bool((config_dict.get("multimodal") or {}).get("vision_encoder_args")
+            or config_dict.get("vision_encoder")):
+        config_dict = _remap_mistral_vision_args(config_dict)
+
+    config = PretrainedConfig.from_dict(config_dict)
+
+    logger.debug("Initialized config", config)
+
+    return config
+
+
+def _remap_mistral_vision_args(config: dict) -> dict:
+    if config.get("multimodal"):
+        vision_config = config.pop("multimodal")
+    else:
+        vision_config = config.pop("vision_encoder")
+
+    quant_config = config.get("quantization_config")
+    config = {
+        "model_type": "pixtral",
+        "architectures": ["PixtralForConditionalGeneration"],
+        "text_config": PretrainedConfig.from_dict(config),
+        "vision_config": PretrainedConfig.from_dict(vision_config),
+    }
+    if quant_config:
+        config["quantization_config"] = quant_config
+    return config
+
+
+def _remap_mistral_yarn_args(config: dict) -> dict:
+    # Direct remaps: yarn.X -> rope_scaling.Y
+    # Source keys are from mistral.model.args.YarnArgs
+    _map = {
+        "beta": "beta_fast",
+        "alpha": "beta_slow",
+    }
+    yarn_config = config.get("yarn") or {}
+    renamed_yarn_config = {_map.get(k, k): v for k, v in yarn_config.items()}
+    config["rope_scaling"] = {
+        "rope_type": "yarn",
+        "mscale_all_dim": 1,  # We hardcoded this to 1
+        **renamed_yarn_config
+    }
+    return config
+
+
+def _remap_general_mistral_args(config: dict) -> dict:
+    # Mistral key -> HF key
+    config_mapping = {
+        "dim": "hidden_size",
+        "norm_eps": "rms_norm_eps",
+        "n_kv_heads": "num_key_value_heads",
+        "n_layers": "num_hidden_layers",
+        "n_heads": "num_attention_heads",
+        "hidden_dim": "intermediate_size",
+    }
+    # HF key -> (Mistral key, default value)
+    top_level_mapping_with_default = {
+        "model_type": ("model_type", "transformer"),
+        "hidden_act": ("activation", "silu"),
+        "tie_word_embeddings": ("tied_embeddings", False),
+        "max_seq_len": ("max_seq_len", 128_000),
+        "max_position_embeddings": ("max_position_embeddings", 128_000),
+    }
+
+    for key, new_key in config_mapping.items():
+        if key in config:
+            config[new_key] = config.pop(key)
+
+    for new_key, (key,
+                  default_value) in top_level_mapping_with_default.items():
+        config[new_key] = config.pop(key, default_value)
+
+    return config
+
+
+def _remap_mistral_quantization_args(config: dict) -> dict:
+    quantization = config.get("quantization", {})
+    if quantization.get("qformat_weight") == "fp8_e4m3":
+        # This maps to the FP8 static per-tensor quantization scheme
+        quantization_config = {
+            "quant_method": "fp8",
+            "activation_scheme": "static"
+        }
+    elif quantization.get("quant_method") == "compressed-tensors":
+        # Pass through the quantization config to compressed-tensors
+        quantization_config = quantization
+    else:
+        raise ValueError(
+            f"Found unknown quantization='{quantization}' in config")
+
+    config["quantization_config"] = quantization_config
+
+    return config