Fixed bug in Linear8bitLt, when the bias is None.

1 files changed, 3 insertions, 3 deletions

diff --git a/bitsandbytes/nn/modules.py b/bitsandbytes/nn/modules.py
index 24ecf39..b222f54 100644
--- a/bitsandbytes/nn/modules.py
+++ b/bitsandbytes/nn/modules.py
@@ -248,10 +248,10 @@ class Linear8bitLt(nn.Linear):
 
         if self.weight.CB is not None:
             self.init_8bit_state()
-        if self.bias.dtype != torch.float16:
+
+        # weights are cast automatically as Int8Params, but the bias has to be cast manually
+        if self.bias is not None and self.bias.dtype != torch.float16:
             self.bias.data = self.bias.data.half()
-        # assert not self.state.has_fp16_weights
-        # if not self.state.has_fp16_weights: assert self.state.CB is not None or self.state.CxB is not None
 
         out = bnb.matmul(x, self.weight, bias=self.bias, state=self.state)