fixed test for int4wo and add __init__.py

Author: Hanxian97

test/quantization/test_mixed_precision.py

@@ -1,11 +1,7 @@
 import torch
 import torch.nn as nn
 
-import os
-import sys
-# append the path to the naive_intNwo.py file
-sys.path.append(os.path.join(os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__)))), "torchao/quantization/prototype/mixed_precision/scripts"))
-from naive_intNwo import intN_weight_only
+from torchao.quantization.prototype.mixed_precision.scripts.naive_intNwo import intN_weight_only
 
 from torchao.quantization import quantize_, int8_weight_only, int4_weight_only
 
@@ -18,11 +14,11 @@
 )
 
 def test_weight_only_quant(quantization_bit=2, symmetric=False):
-    for x_shape in [[32, 64], [80, 80, 80, 64], [16, 64, 64]]:
-        x = torch.randn(*x_shape)
-        m = nn.Sequential(nn.Linear(64, 80))
+    for x_shape in [[64, 32], [80, 80, 80, 32], [16, 64, 32]]:
+        x = torch.randn(*x_shape, dtype=torch.bfloat16)
+        m = nn.Sequential(nn.Linear(32, 80)).bfloat16()
         y_ref = m(x)
-        quantize_(m, intN_weight_only(n=quantization_bit, group_size=16, symmetric=symmetric))
+        quantize_(m, intN_weight_only(n=quantization_bit, group_size=32, symmetric=symmetric))
         y_wo = m(x)
         sqnr = compute_error(y_ref, y_wo)
         #SQNR_dB can be approximated by 6.02n, where n is the bit width of the quantization
@@ -31,7 +27,7 @@ def test_weight_only_quant(quantization_bit=2, symmetric=False):
 
 
 # test if the asymmetric and symmetric quantization API works with different bit widths
-for i in [2,3,5,6,8]:
+for i in [2, 3, 4, 5, 6, 8]:
     #test for asymmetric quantization
     try:
         test_weight_only_quant(i, False)

torchao/quantization/prototype/mixed_precision/__init__.py

@@ -0,0 +1 @@
+from .naive_intNwo import intN_weight_only