convert: add tensor hash general.hash.sha256 to kv store

convert_hf_to_gguf.py

@@ -384,6 +384,12 @@ def prepare_metadata(self, vocab_only: bool):
 
         self.set_type()
 
+        # Generate sha256 based on tensor content if required
+        if not vocab_only:
+            hash_sha256 = self.gguf_writer.calculate_tensor_hash_sha256()
+            self.gguf_writer.add_hash_sha256(hash_sha256)
+            logger.info(f"tensor hash (sha256): {hash_sha256}")
+
         logger.info("Set meta model")
         self.metadata.set_gguf_meta_model(self.gguf_writer)
 

gguf-py/gguf/constants.py

@@ -25,6 +25,9 @@ class General:
         ALIGNMENT                  = "general.alignment"
         FILE_TYPE                  = "general.file_type"
 
+        # Tensor Hash
+        HASH_SHA256                = "general.hash.sha256"
+
         # Authorship Metadata
         NAME                       = "general.name"
         AUTHOR                     = "general.author"

gguf-py/gguf/gguf_writer.py

@@ -2,6 +2,7 @@
 
 import logging
 import os
+import hashlib
 import shutil
 import struct
 import tempfile
@@ -417,6 +418,18 @@ def write_tensor_data(self, tensor: np.ndarray[Any, Any]) -> None:
 
         self.state = WriterState.WEIGHTS
 
+    def calculate_tensor_hash_sha256(self) -> str:
+        sha256 = hashlib.sha256()
+
+        for tensors in self.tensors:
+            # relying on the fact that Python dicts preserve insertion order (since 3.7)
+            for _, ti in tensors.items():
+                assert ti.tensor is not None
+                assert ti.tensor.nbytes == ti.nbytes
+                sha256.update(ti.tensor.tobytes('C'))
+
+        return sha256.hexdigest()
+
     def write_tensors_to_file(self, *, progress: bool = False) -> None:
         self.write_ti_data_to_file()
 
@@ -491,6 +504,9 @@ def add_custom_alignment(self, alignment: int) -> None:
     def add_file_type(self, ftype: int) -> None:
         self.add_uint32(Keys.General.FILE_TYPE, ftype)
 
+    def add_hash_sha256(self, hash: str) -> None:
+        self.add_string(Keys.General.HASH_SHA256, hash)
+
     def add_name(self, name: str) -> None:
         self.add_string(Keys.General.NAME, name)