Refactor: convert_hf_to_gguf.py (#17114)

* move conversion code to a dedicated conversion directory and split the files akin to the src/models architecture

---------

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

conversion/refact.py

@@ -0,0 +1,68 @@
+from __future__ import annotations
+
+from typing import Iterable, TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from torch import Tensor
+
+from .base import ModelBase, TextModel, gguf
+
+
+@ModelBase.register("GPTRefactForCausalLM")
+class RefactModel(TextModel):
+    model_arch = gguf.MODEL_ARCH.REFACT
+
+    def set_vocab(self):
+        super().set_vocab()
+
+        # TODO: how to determine special FIM tokens automatically?
+        special_vocab = gguf.SpecialVocab(self.dir_model, load_merges=False,
+                                          special_token_types = ['prefix', 'suffix', 'middle', 'eot'])
+        special_vocab._set_special_token("prefix", 1)
+        special_vocab._set_special_token("suffix", 3)
+        special_vocab._set_special_token("middle", 2)
+        special_vocab.chat_template = None  # do not add it twice
+        special_vocab.add_to_gguf(self.gguf_writer)
+
+    def set_gguf_parameters(self):
+        hidden_dim = self.hparams["n_embd"]
+        inner_dim = 4 * hidden_dim
+        hidden_dim = int(2 * inner_dim / 3)
+        multiple_of = 256
+        ff_dim = multiple_of * ((hidden_dim + multiple_of - 1) // multiple_of)
+
+        # refact uses Alibi. So this is from config.json which might be used by training.
+        self.gguf_writer.add_context_length(self.hparams["n_positions"])
+        self.gguf_writer.add_embedding_length(self.hparams["n_embd"])
+
+        self.gguf_writer.add_feed_forward_length(ff_dim)
+        self.gguf_writer.add_block_count(self.block_count)
+        self.gguf_writer.add_head_count(self.hparams["n_head"])
+        self.gguf_writer.add_head_count_kv(1)
+        self.gguf_writer.add_layer_norm_rms_eps(self.hparams["layer_norm_epsilon"])
+        self.gguf_writer.add_file_type(self.ftype)
+
+    def modify_tensors(self, data_torch: Tensor, name: str, bid: int | None) -> Iterable[tuple[str, Tensor]]:
+        hidden_dim = self.hparams["n_embd"]
+        inner_dim = 4 * hidden_dim
+        hidden_dim = int(2 * inner_dim / 3)
+        multiple_of = 256
+        ff_dim = multiple_of * ((hidden_dim + multiple_of - 1) // multiple_of)
+        n_head = self.hparams["n_head"]
+        n_head_kv = 1
+        head_dim = self.hparams["n_embd"] // n_head
+
+        if bid is not None:
+            if name == f"transformer.h.{bid}.attn.kv.weight":
+                yield from super().modify_tensors(data_torch[:n_head_kv * head_dim], self.format_tensor_name(gguf.MODEL_TENSOR.ATTN_K, bid), bid)
+                yield from super().modify_tensors(data_torch[n_head_kv * head_dim:], self.format_tensor_name(gguf.MODEL_TENSOR.ATTN_V, bid), bid)
+                return
+            if name == f"transformer.h.{bid}.attn.q.weight":
+                yield from super().modify_tensors(data_torch, self.format_tensor_name(gguf.MODEL_TENSOR.ATTN_Q, bid), bid)
+                return
+            if name == f"transformer.h.{bid}.mlp.gate_up_proj.weight":
+                yield from super().modify_tensors(data_torch[:ff_dim], self.format_tensor_name(gguf.MODEL_TENSOR.FFN_GATE, bid), bid)
+                yield from super().modify_tensors(data_torch[ff_dim:], self.format_tensor_name(gguf.MODEL_TENSOR.FFN_UP, bid), bid)
+                return
+
+        yield from super().modify_tensors(data_torch, name, bid)