model : add sarvam_moe architecture support (#20275)

convert_hf_to_gguf.py

@@ -1570,6 +1570,9 @@ class TextModel(ModelBase):
         if chkhsh == "862f827721df956049dff5ca81a57f29e575280bc622e290d3bf4e35eca29015":
             # ref: https://huggingface.co/codefuse-ai/F2LLM-v2-4B
             res = "f2llmv2"
+        if chkhsh == "62f6fb0a6fd5098caeabb19b07a5c1099cafc8b9c40eab6ea89ece4ec02fbc57":
+            # ref: https://huggingface.co/sarvamai/sarvam-30b
+            res = "sarvam-moe"
 
         if res is None:
             logger.warning("\n")
@@ -11591,6 +11594,34 @@ class BailingMoeV2Model(TextModel):
                 raise ValueError(f"Unprocessed experts: {experts}")
 
 
+@ModelBase.register("SarvamMoEForCausalLM", "modeling_sarvam_moe.SarvamMoEForCausalLM")
+class SarvamMoEModel(BailingMoeV2Model):
+    model_arch = gguf.MODEL_ARCH.BAILINGMOE2
+    # Sarvam-MoE shares the BailingMoeV2 architecture; only differences:
+    #  - full rotary (no partial_rotary_factor)
+    #  - expert bias is zero-mean normalized at load time
+
+    def set_gguf_parameters(self):
+        super().set_gguf_parameters()
+        hparams = self.hparams
+        if (rope_dim := hparams.get("head_dim")) is None:
+            rope_dim = hparams["hidden_size"] // hparams["num_attention_heads"]
+        # Override the partial-rotary value written by BailingMoeV2 with the full rotary dim
+        self.gguf_writer.add_rope_dimension_count(rope_dim)
+
+    @classmethod
+    def filter_tensors(cls, item: tuple[str, Callable[[], Tensor]]) -> tuple[str, Callable[[], Tensor]] | None:
+        name, gen = item
+        if name.endswith(".expert_bias"):
+            # Sarvam normalizes expert bias to zero mean
+            inner = gen
+
+            def gen():
+                t = inner()
+                return t - t.mean()
+        return super().filter_tensors((name, gen))
+
+
 @ModelBase.register("GroveMoeForCausalLM", "modeling_grove_moe.GroveMoeForCausalLM")
 class GroveMoeModel(TextModel):
     model_arch = gguf.MODEL_ARCH.GROVEMOE