Fix zero-dim tensor concatenation in compressor scale buffer

input_scale and weight_scale_2 are 0-dim scalars in the NVFP4 checkpoint.
torch.cat can't concatenate scalars — reshape to 1-d first.

vllm/patches/deepseek_v4.py

@@ -1611,8 +1611,15 @@ class DeepseekV4Model(nn.Module):
                 continue
             param = params_dict[name]
             if len(shards) == 2:
-                # Concatenate shard 0 and shard 1 along dim 0
-                stacked = torch.cat([shards[0], shards[1]], dim=0)
+                # Concatenate shard 0 and shard 1 along dim 0.
+                # Scales may be 0-dim scalars (input_scale, weight_scale_2)
+                # or N-dim tensors (weight_scale); reshape scalars to 1-d.
+                s0, s1 = shards[0], shards[1]
+                if s0.ndim == 0:
+                    s0 = s0.reshape(1)
+                if s1.ndim == 0:
+                    s1 = s1.reshape(1)
+                stacked = torch.cat([s0, s1], dim=0)
             else:
                 stacked = shards[0]
             assert param.data.shape == stacked.shape, (