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Co-authored-by: Lőrinc Pap <[email protected]>

src/lib.rs

@@ -23,7 +23,7 @@ fn _byte_pair_merge(ranks: &HashMap<Vec<u8>, Rank>, piece: &[u8]) -> Vec<(usize,
     // Note that we hash bytes when indexing into `ranks`, not token pairs. As long as we train BPE
     // the way we currently do, this is equivalent. An easy way to break this would be to decouple
     // merge priority from token index or to prevent specific token merges.
-    let mut min_rank: (Rank, usize) = (Rank::MAX, 0);
+    let mut min_rank: (Rank, usize) = (Rank::MAX, usize::MAX);
     for i in 0..piece.len() - 1 {
         let rank = *ranks.get(&piece[i..i + 2]).unwrap_or(&Rank::MAX);
         if rank < min_rank.0 {
@@ -57,13 +57,13 @@ fn _byte_pair_merge(ranks: &HashMap<Vec<u8>, Rank>, piece: &[u8]) -> Vec<(usize,
         let i = min_rank.1;
         // Update parts[i] and parts[i - 1] before removing parts[i + 1], since
         // `parts.remove(i + 1)` will thrash the cache.
-        parts[i].1 = get_rank(&parts, i);
         if i > 0 {
             parts[i - 1].1 = get_rank(&parts, i - 1);
         }
+        parts[i].1 = get_rank(&parts, i);
         parts.remove(i + 1);
 
-        min_rank = (Rank::MAX, 0);
+        min_rank = (Rank::MAX, usize::MAX);
         for (i, &(_, rank)) in parts[..parts.len() - 1].iter().enumerate() {
             if rank < min_rank.0 {
                 min_rank = (rank, i);