loosen restriction around needing an separate optimizer for learnable codebook

Author: lucidrains

setup.py

@@ -3,7 +3,7 @@
 setup(
   name = 'vector_quantize_pytorch',
   packages = find_packages(),
-  version = '1.6.22',
+  version = '1.6.23',
   license='MIT',
   description = 'Vector Quantization - Pytorch',
   long_description_content_type = 'text/markdown',

vector_quantize_pytorch/vector_quantize_pytorch.py

@@ -689,8 +689,6 @@ def __init__(
         self.orthogonal_reg_max_codes = orthogonal_reg_max_codes
 
         assert not (ema_update and learnable_codebook), 'learnable codebook not compatible with EMA update'
-        assert not learnable_codebook or (learnable_codebook and in_place_codebook_optimizer is not None), \
-                'Must specify an optimizer for the codebook embedding if learnable_codebook is set to True'
 
         assert 0 <= sync_update_v <= 1.
         assert not (sync_update_v > 0. and not learnable_codebook), 'learnable codebook must be turned on'