fix a performance bug in drop

kaikalii · kaikalii · commit cf35be3decce · 2025-11-03T10:03:10.000-08:00
diff --git a/src/algorithm/dyadic/structure.rs b/src/algorithm/dyadic/structure.rs
@@ -756,10 +756,10 @@ impl<T: ArrayValue> Array<T> {
                 let row_count = self.row_count();
                 let abs_dropping = dropping.unsigned_abs().min(row_count);
                 if dropping >= 0 {
-                    self.data.as_mut_slice().rotate_left(abs_dropping * row_len);
+                    self.data = self.data.slice(abs_dropping * row_len..)
+                } else {
                     self.data.truncate((row_count - abs_dropping) * row_len);
                 }
-                self.data.truncate((row_count - abs_dropping) * row_len);
                 if self.shape.is_empty() {
                     self.shape.push(1);
                 }

Original file line number	Diff line number	Diff line change
`@@ -756,10 +756,10 @@ impl<T: ArrayValue> Array<T> {`
`756`	`756`	`let row_count = self.row_count();`
`757`	`757`	`let abs_dropping = dropping.unsigned_abs().min(row_count);`
`758`	`758`	`if dropping >= 0 {`
`759`		`- self.data.as_mut_slice().rotate_left(abs_dropping * row_len);`
	`759`	`+ self.data = self.data.slice(abs_dropping * row_len..)`
	`760`	`+ } else {`
`760`	`761`	`self.data.truncate((row_count - abs_dropping) * row_len);`
`761`	`762`	`}`
`762`		`- self.data.truncate((row_count - abs_dropping) * row_len);`
`763`	`763`	`if self.shape.is_empty() {`
`764`	`764`	`self.shape.push(1);`
`765`	`765`	`}`