- set default transform center to -0.5

src/transform.rs

@@ -410,7 +410,7 @@ impl<D: Dimension> Default for Transform<D> {
         Self {
             parameters,
             dparameters: vec![0f64; ndim * ndim + ndim],
-            center: vec![0f64; ndim],
+            center: vec![-0.5; ndim],
             shape: vec![0usize; ndim],
             dimension: PhantomData,
         }
@@ -997,6 +997,28 @@ impl<D: Dimension> Transform<D> {
             dimension: Default::default(),
         }
     }
+    
+    pub fn swap_axes(&self, a: usize, b: usize) -> Self {
+        let mut new = self.clone();
+        let n = self.ndim();
+        let mut m = (0..n).collect::<Vec<_>>();
+        (m[a], m[b]) = (m[b], m[a]);
+        for (i, j) in (0..n).zip(m) {
+            if i != j {
+                new.parameters[i + n * j] = self.parameters[j + n * i];
+                new.dparameters[i + n * j] = self.dparameters[j + n * i];
+                new.parameters[j + n * i] = self.parameters[i + n * j];
+                new.dparameters[j + n * i] = self.dparameters[i + n * j];
+            }
+        }
+        new.parameters[n + a] = self.parameters[n + b];
+        new.dparameters[n + a] = self.dparameters[n + b];
+        new.center[a] = self.center[b];
+        new.center[b] = self.center[a];
+        new.shape[a] = self.shape[b];
+        new.shape[b] = self.shape[a];
+        new
+    }
 }
 
 impl Transform<Ix2> {