diff --git a/models/etsformer/exponential_smoothing.py b/models/etsformer/exponential_smoothing.py
index 96c167d..d48c108 100644
--- a/models/etsformer/exponential_smoothing.py
+++ b/models/etsformer/exponential_smoothing.py
@@ -20,7 +20,7 @@ def conv1d_fft(f, g, dim=-1):
     F_fg = F_f * F_g.conj()
     out = fft.irfft(F_fg, fast_len, dim=dim)
     out = out.roll((-1,), dims=(dim,))
-    idx = torch.as_tensor(range(fast_len - N, fast_len)).to(out.device)
+    idx = torch.arange(fast_len - N, fast_len, device=out.device)
     out = out.index_select(dim, idx)
 
     return out