convert : remove input_scale for dequantized fp8 modelopt (#22356)

This commit is contained in:
Sigbjørn Skjæret
2026-04-27 08:45:01 +02:00
committed by GitHub
parent f84270ea10
commit d13540becd
+21 -30
View File
@@ -272,6 +272,22 @@ class ModelBase:
return tensors
@staticmethod
def _scale_is_trivial(scale: Tensor) -> bool:
return scale.numel() <= 1 and abs(float(scale.float().sum()) - 1.0) < 1e-6
def _write_scale_tensor(self, scale_name: str, scale: Tensor):
if not self._scale_is_trivial(scale):
scale_f32 = scale.float().numpy().flatten()
logger.info(f" + {scale_name} (per-tensor scale, shape [{scale_f32.size}])")
self.gguf_writer.add_tensor(scale_name, scale_f32)
def _write_scales_tensor(self, scale_name: str, scales: list[float]):
if not np.allclose(scales, 1.0, atol=1e-6):
scale_vals = np.array(scales, dtype=np.float32)
logger.info(f" + {scale_name} (per-expert scale, shape [{len(scales)}])")
self.gguf_writer.add_tensor(scale_name, scale_vals)
def dequant_model(self):
# If all quantized tensors were already handled (e.g. pure NVFP4), skip
if self._is_nvfp4 and not any(k.endswith((".weight_scale", ".weight_scale_inv")) for k in self.model_tensors):
@@ -494,7 +510,7 @@ class ModelBase:
s = self.model_tensors[name]
self.model_tensors[weight_name] = lambda w=w, s=s: dequant_simple(w(), s(), None)
tensors_to_remove.append(name)
if name.endswith((".k_scale", ".v_scale")):
if name.endswith((".input_scale", ".k_scale", ".v_scale")):
tensors_to_remove.append(name)
elif quant_method is not None:
raise NotImplementedError(f"Quant method is not yet supported: {quant_method!r}")
@@ -602,10 +618,6 @@ class ModelBase:
raw = np.concatenate([d_grouped, qs_grouped], axis=-1).reshape(out_features, n_super * 36)
return raw, [out_features, n_super * 64]
@staticmethod
def _nvfp4_scale2_is_trivial(scale2: Tensor) -> bool:
return scale2.numel() <= 1 and abs(float(scale2.float().sum()) - 1.0) < 1e-6
def _repack_nvfp4(self, name: str, weight: Tensor, scale: Tensor, scale2: Tensor, input_scale: Tensor):
if "language_model." in name:
name = name.replace("language_model.", "")
@@ -616,19 +628,8 @@ class ModelBase:
logger.info(f"Repacked {new_name} with shape {shape} and quantization NVFP4")
self.gguf_writer.add_tensor(new_name, raw, raw_dtype=gguf.GGMLQuantizationType.NVFP4)
# Emit per-tensor scale2 as a separate F32 tensor when non-trivial
if not self._nvfp4_scale2_is_trivial(scale2):
scale2_f32 = scale2.float().numpy().flatten()
scale_name = new_name.replace(".weight", ".scale")
logger.info(f" + {scale_name} (per-tensor NVFP4 scale2, shape [{scale2_f32.size}])")
self.gguf_writer.add_tensor(scale_name, scale2_f32)
# Emit per-tensor input_scale as a separate F32 tensor when non-trivial
if not self._nvfp4_scale2_is_trivial(input_scale):
input_scale_f32 = input_scale.float().numpy().flatten()
input_scale_name = new_name.replace(".weight", ".input_scale")
logger.info(f" + {input_scale_name} (per-tensor NVFP4 input_scale, shape [{input_scale_f32.size}])")
self.gguf_writer.add_tensor(input_scale_name, input_scale_f32)
self._write_scale_tensor(new_name.replace(".weight", ".scale"), scale2)
self._write_scale_tensor(new_name.replace(".weight", ".input_scale"), input_scale)
def _generate_nvfp4_tensors(self):
# Per-layer expert merging to avoid holding all experts in memory
@@ -719,21 +720,11 @@ class ModelBase:
logger.info(f"Repacked {new_name} with shape [{len(experts)}, {shape[0]}, {shape[1]}] and quantization NVFP4")
self.gguf_writer.add_tensor(new_name, merged, raw_dtype=gguf.GGMLQuantizationType.NVFP4)
# Emit per-expert scale2 tensor if any expert has non-trivial scale2
scales.sort(key=lambda x: x[0])
scale_vals = np.array([s[1] for s in scales], dtype=np.float32)
if not np.allclose(scale_vals, 1.0, atol=1e-6):
scale_name = new_name.replace(".weight", ".scale")
logger.info(f" + {scale_name} (per-expert NVFP4 scale2, shape [{len(scales)}])")
self.gguf_writer.add_tensor(scale_name, scale_vals)
self._write_scales_tensor(new_name.replace(".weight", ".scale"), [s[1] for s in scales])
# Emit per-expert input_scale tensor if any expert has non-trivial input_scale
input_scales.sort(key=lambda x: x[0])
input_scale_vals = np.array([s[1] for s in input_scales], dtype=np.float32)
if not np.allclose(input_scale_vals, 1.0, atol=1e-6):
input_scale_name = new_name.replace(".weight", ".input_scale")
logger.info(f" + {input_scale_name} (per-expert NVFP4 input_scale, shape [{len(input_scales)}])")
self.gguf_writer.add_tensor(input_scale_name, input_scale_vals)
self._write_scales_tensor(new_name.replace(".weight", ".input_scale"), [s[1] for s in input_scales])
del experts, merged