Rewrite drop_{upper,lower} for ArrayBase<S, Ix2>

Author: termoshtt

src/triangular.rs

@@ -1,5 +1,5 @@
 
-use ndarray::{Ix2, Array};
+use ndarray::{Ix2, Array, NdFloat, ArrayBase, DataMut};
 
 use matrix::{Matrix, MFloat};
 use square::SquareMatrix;
@@ -32,19 +32,23 @@ impl<A: MFloat> TriangularMatrix for Array<A, Ix2> {
     }
 }
 
-pub fn drop_upper(mut a: Array<f64, Ix2>) -> Array<f64, Ix2> {
+pub fn drop_upper<A: NdFloat, S>(mut a: ArrayBase<S, Ix2>) -> ArrayBase<S, Ix2>
+    where S: DataMut<Elem = A>
+{
     for ((i, j), val) in a.indexed_iter_mut() {
         if i < j {
-            *val = 0.0;
+            *val = A::zero();
         }
     }
     a
 }
 
-pub fn drop_lower(mut a: Array<f64, Ix2>) -> Array<f64, Ix2> {
+pub fn drop_lower<A: NdFloat, S>(mut a: ArrayBase<S, Ix2>) -> ArrayBase<S, Ix2>
+    where S: DataMut<Elem = A>
+{
     for ((i, j), val) in a.indexed_iter_mut() {
         if i > j {
-            *val = 0.0;
+            *val = A::zero();
         }
     }
     a