fix mask bug

src/utils/tensor_utils.rs

@@ -21,14 +21,14 @@ pub fn prepare_causal_attention_mask(
         .collect();
     let mask = Tensor::from_slice(&mask, (tgt_len, tgt_len), device)?;
     let mask = if seqlen_offset > 0 {
-        let mask0 = Tensor::zeros((tgt_len, seqlen_offset), DType::U32, device)?;
+        let mask0 = Tensor::zeros((tgt_len, seqlen_offset), DType::F32, device)?;
         Tensor::cat(&[&mask0, &mask], D::Minus1)?
     } else {
         mask
     };
     let mask = mask
         .expand((b_size, 1, tgt_len, tgt_len + seqlen_offset))?
-        .to_dtype(DType::U32)?;
+        .to_dtype(DType::F32)?;
     Ok(mask)
 }