Limit the scale minimum value not to 0 (#209)

Signed-off-by: Zhang, Weiwei1 <[email protected]>

auto_round/data_type/int.py

@@ -19,7 +19,7 @@
 
 @register_dtype("int_asym")
 def quant_tensor_asym(weight, num_bits=4, v=0, min_scale=1.0, max_scale=1.0, scale_dtype=torch.float16,
-                      weight_min=None, weight_max=None, q_scale_thresh=0.0,**kwargs):
+                      weight_min=None, weight_max=None, q_scale_thresh=0.0 ,**kwargs):
     """Quantizes and dequantizes weight asymmetrically.
 
     Args:
@@ -59,6 +59,8 @@ def quant_tensor_asym(weight, num_bits=4, v=0, min_scale=1.0, max_scale=1.0, sca
     wmax[tmp] = +1
     scale = ((wmax - wmin) / maxq).to(scale_dtype)
     scale = torch.clamp(scale, min=q_scale_thresh)
+    if (scale == 0.).any():
+        scale = torch.clamp(scale, min=1e-5)
     zp = round_ste(-wmin / scale)  # pylint: disable=E1130
     scale = scale.unsqueeze(dim=-1)
     zp = zp.unsqueeze(dim=-1)
@@ -68,7 +70,7 @@ def quant_tensor_asym(weight, num_bits=4, v=0, min_scale=1.0, max_scale=1.0, sca
 
 @register_dtype("int_sym")
 def quant_tensor_sym(weight, num_bits=4, v=0, min_scale=1.0, max_scale=1.0, scale_dtype=torch.float16, weight_min=None,
-                     weight_max=None, q_scale_thresh=0.0,**kargs):
+                     weight_max=None, q_scale_thresh=0.0, **kargs):
     """Quantizes and dequantizes weight symmetrically.
 
     Args:
@@ -114,9 +116,12 @@ def quant_tensor_sym(weight, num_bits=4, v=0, min_scale=1.0, max_scale=1.0, scal
     wmax_new[tmp] = +1
     scale = ((wmax_new - wmin_new) / maxq).to(scale_dtype)
     scale = torch.clamp(scale, min=q_scale_thresh)
+    if (scale == 0.).any():
+        scale = torch.clamp(scale, min=1e-5)
     scale = scale.unsqueeze(dim=-1)
     zp = torch.full_like(scale, (maxq + 1) / 2)
 
     int_w = round_ste(weight / scale + v)
     q = torch.clamp(int_w + zp, 0, maxq)
     return scale * (q - zp), scale, zp
+