Rework byteswapping code in gguf-py

Move out details from byteswapping tensor blocks code

Author: AlekseiNikiforovIBM

gguf-py/gguf/scripts/gguf_convert_endian.py

@@ -19,6 +19,61 @@
 logger = logging.getLogger("gguf-convert-endian")
 
 
+def byteswap_q4_0(tensor, block_offs):
+    # Each block_q4_0 consists of an f16 delta (scaling factor) followed by 16 int8 quantizations.
+
+    # Byte-Swap f16 sized delta field
+    delta = tensor.data[block_offs:block_offs + 2].view(dtype=np.uint16)
+    delta.byteswap(inplace=True)
+
+
+def byteswap_q8_0(tensor, block_offs):
+    # Each block_q8_0 consists of an f16 delta (scaling factor) followed by 32 int8 quantizations.
+
+    # Byte-Swap f16 sized delta field
+    delta = tensor.data[block_offs:block_offs + 2].view(dtype=np.uint16)
+    delta.byteswap(inplace=True)
+
+
+def byteswap_q4_k(tensor, block_offs):
+    # Each block_q4_k consists of 2 f16 values followed by 140 int8 values.
+
+    # Byte-Swap f16 sized fields
+    delta = tensor.data[block_offs:block_offs + 2].view(dtype=np.uint16)
+    delta.byteswap(inplace=True)
+
+    delta = tensor.data[block_offs + 2:block_offs + 4].view(dtype=np.uint16)
+    delta.byteswap(inplace=True)
+
+
+def byteswap_q6_k(tensor, block_offs):
+    # Each block_q6_k consists of 208 int8 values followed by 1 f16 value.
+
+    # Byte-Swap f16 sized field
+    delta = tensor.data[block_offs + 208:block_offs + 210].view(dtype=np.uint16)
+    delta.byteswap(inplace=True)
+
+
+byteswap_tensors = {
+    gguf.GGMLQuantizationType.Q4_0: {
+        "block_size": 18, # 18 bytes = <f16 delta scaling factor> + 16 * <int8 quant>
+        "byteswap_func": byteswap_q4_0,
+    },
+    gguf.GGMLQuantizationType.Q8_0: {
+        "block_size": 34, # 34 bytes = <f16 delta scaling factor> + 32 * <int8 quant>
+        "byteswap_func": byteswap_q8_0,
+    },
+    gguf.GGMLQuantizationType.Q4_K: {
+        "block_size": 144, # 144 bytes = 2 * <f16 delta scaling factor> + 140 * <int8 quant>
+        "byteswap_func": byteswap_q4_k,
+    },
+    gguf.GGMLQuantizationType.Q6_K: {
+        "block_size": 210, # 210 bytes = <f16 delta scaling factor> + 208 * <int8 quant>
+        "byteswap_func": byteswap_q6_k,
+    },
+}
+
+
 def convert_byteorder(reader: gguf.GGUFReader, args: argparse.Namespace) -> None:
     file_endian = reader.endianess.name
     if reader.byte_order == 'S':
@@ -32,14 +87,11 @@ def convert_byteorder(reader: gguf.GGUFReader, args: argparse.Namespace) -> None
         sys.exit(0)
     logger.info("* Checking tensors for conversion compatibility")
     for tensor in reader.tensors:
-        if tensor.tensor_type not in (
-            gguf.GGMLQuantizationType.F32,
-            gguf.GGMLQuantizationType.F16,
-            gguf.GGMLQuantizationType.Q4_0,
-            gguf.GGMLQuantizationType.Q8_0,
-            gguf.GGMLQuantizationType.Q4_K,
-            gguf.GGMLQuantizationType.Q6_K,
-        ):
+        if tensor.tensor_type not in byteswap_tensors and \
+           tensor.tensor_type not in (
+                gguf.GGMLQuantizationType.F32,
+                gguf.GGMLQuantizationType.F16,
+           ):
             raise ValueError(f"Cannot handle type {tensor.tensor_type.name} for tensor {repr(tensor.name)}")
     logger.info(f"* Preparing to convert from {file_endian} to {order}")
     if args.dry_run:
@@ -73,40 +125,7 @@ def convert_byteorder(reader: gguf.GGUFReader, args: argparse.Namespace) -> None
             part.byteswap(inplace=True)
 
         # Byte-swap tensor data if necessary
-        if tensor.tensor_type == gguf.GGMLQuantizationType.Q4_0:
-            # Handle Q4_0 tensor blocks (block_q4_0)
-            # Specific handling of block_q4_0 is required.
-            # Each block_q4_0 consists of an f16 delta (scaling factor) followed by 16 int8 quantizations.
-
-            # first flatten structure
-            oldshape = tensor.data.shape
-            newshape = 1
-            for i in tensor.data.shape:
-                newshape *= i
-
-            tensor.data.resize(newshape)
-
-            block_size = 18 # 18 bytes = <f16 delta scaling factor> + 16 * <int8 quant>
-
-            n_blocks = len(tensor.data) // block_size
-            for block_num in (inner_pbar := tqdm(range(n_blocks), desc="Byte-swapping Blocks", leave=False)):
-                block_offs = block_num * block_size
-
-                # Byte-Swap f16 sized delta field
-                delta = tensor.data[block_offs:block_offs + 2].view(dtype=np.uint16)
-                delta.byteswap(inplace=True)
-
-                # Byte-Swap Q8 weights
-                if block_num % 100000 == 0:
-                    inner_pbar.set_description(f"Byte-swapping Blocks [{(n_blocks - block_num) // n_blocks}]")
-
-            # restore old shape in case it's ever used
-            tensor.data.resize(oldshape)
-        elif tensor.tensor_type == gguf.GGMLQuantizationType.Q8_0:
-            # Handle Q8_0 tensor blocks (block_q8_0)
-            # Specific handling of block_q8_0 is required.
-            # Each block_q8_0 consists of an f16 delta (scaling factor) followed by 32 int8 quantizations.
-
+        if tensor.tensor_type in byteswap_tensors:
             # first flatten structure
             oldshape = tensor.data.shape
             newshape = 1
@@ -115,76 +134,15 @@ def convert_byteorder(reader: gguf.GGUFReader, args: argparse.Namespace) -> None
 
             tensor.data.resize(newshape)
 
-            block_size = 34 # 34 bytes = <f16 delta scaling factor> + 32 * <int8 quant>
-
-            n_blocks = len(tensor.data) // block_size
-            for block_num in (inner_pbar := tqdm(range(n_blocks), desc="Byte-swapping Blocks", leave=False)):
-                block_offs = block_num * block_size
-
-                # Byte-Swap f16 sized delta field
-                delta = tensor.data[block_offs:block_offs + 2].view(dtype=np.uint16)
-                delta.byteswap(inplace=True)
-
-                # Byte-Swap Q8 weights
-                if block_num % 100000 == 0:
-                    inner_pbar.set_description(f"Byte-swapping Blocks [{(n_blocks - block_num) // n_blocks}]")
-
-            # restore old shape in case it's ever used
-            tensor.data.resize(oldshape)
-        elif tensor.tensor_type == gguf.GGMLQuantizationType.Q4_K:
-            # Handle Q4_K tensor blocks (block_q4_k)
-            # Specific handling of block_q4_k is required.
-            # Each block_q4_k consists of 2 f16 values followed by 140 int8 values.
-
-            # first flatten structure
-            oldshape = tensor.data.shape
-            newshape = 1
-            for i in tensor.data.shape:
-                newshape *= i
-
-            tensor.data.resize(newshape)
-
-            block_size = 144
-            n_blocks = len(tensor.data) // block_size
-            for block_num in (inner_pbar := tqdm(range(n_blocks), desc="Byte-swapping Blocks", leave=False)):
-                block_offs = block_num * block_size
-
-                # Byte-Swap f16 sized fields
-                delta = tensor.data[block_offs:block_offs + 2].view(dtype=np.uint16)
-                delta.byteswap(inplace=True)
-
-                delta = tensor.data[block_offs + 2:block_offs + 4].view(dtype=np.uint16)
-                delta.byteswap(inplace=True)
-
-                # Byte-Swap
-                if block_num % 100000 == 0:
-                    inner_pbar.set_description(f"Byte-swapping Blocks [{(n_blocks - block_num) // n_blocks}]")
-
-            # restore old shape in case it's ever used
-            tensor.data.resize(oldshape)
-        elif tensor.tensor_type == gguf.GGMLQuantizationType.Q6_K:
-            # Handle Q6_K tensor blocks (block_q6_k)
-            # Specific handling of block_q6_k is required.
-            # Each block_q6_k consists of 208 int8 values followed by 1 f16 value.
-
-            # first flatten structure
-            oldshape = tensor.data.shape
-            newshape = 1
-            for i in tensor.data.shape:
-                newshape *= i
-
-            tensor.data.resize(newshape)
+            block_size    = byteswap_tensors[tensor.tensor_type]["block_size"]
+            byteswap_func = byteswap_tensors[tensor.tensor_type]["byteswap_func"]
 
-            block_size = 210
             n_blocks = len(tensor.data) // block_size
             for block_num in (inner_pbar := tqdm(range(n_blocks), desc="Byte-swapping Blocks", leave=False)):
                 block_offs = block_num * block_size
 
-                # Byte-Swap f16 sized field
-                delta = tensor.data[block_offs + 208:block_offs + 210].view(dtype=np.uint16)
-                delta.byteswap(inplace=True)
+                byteswap_func(tensor, block_offs)
 
-                # Byte-Swap
                 if block_num % 100000 == 0:
                     inner_pbar.set_description(f"Byte-swapping Blocks [{(n_blocks - block_num) // n_blocks}]")