Implement Outer for DVec. (#186)

Fix #181.

src/structs/dvec.rs

@@ -7,7 +7,8 @@ use std::ops::{Add, Sub, Mul, Div, Neg, AddAssign, SubAssign, MulAssign, DivAssi
 use std::mem;
 use rand::{self, Rand};
 use num::{Zero, One};
-use traits::operations::{ApproxEq, Axpy, Mean};
+use structs::DMat;
+use traits::operations::{ApproxEq, Axpy, Mean, Outer};
 use traits::geometry::{Dot, Norm};
 use traits::structure::{Iterable, IterableMut, Indexable, Shape, BaseFloat, BaseNum, Cast};
 #[cfg(feature="arbitrary")]
@@ -74,6 +75,25 @@ impl<N> FromIterator<N> for DVec<N> {
     }
 }
 
+impl<N: Copy + BaseNum> Outer for DVec<N> {
+    type OuterProductType = DMat<N>;
+
+    #[inline]
+    fn outer(&self, other: &DVec<N>) -> DMat<N> {
+        let mut res = unsafe { DMat::new_uninitialized(self.at.len(), other.at.len()) };
+
+        for i in 0 .. self.at.len() {
+            for j in 0 .. other.at.len() {
+                unsafe {
+                    res.unsafe_set((i, j), self.unsafe_at(i) * other.unsafe_at(j));
+                }
+            }
+        }
+
+        res
+    }
+}
+
 #[cfg(feature="arbitrary")]
 impl<N: Arbitrary> Arbitrary for DVec<N> {
     fn arbitrary<G: Gen>(g: &mut G) -> DVec<N> {

tests/mat.rs

@@ -835,3 +835,11 @@ fn test_transpose_square_mat() {
         assert_eq!(&[0, 1, 2, 3], &mat.row_slice(i, 0, num_cols)[..]);
     }
 }
+
+#[test]
+fn test_outer_dvec() {
+    let vec = DVec::from_slice(5, &[ 1.0, 2.0, 3.0, 4.0, 5.0 ]);
+    let row = DMat::from_row_vec(1, 5, &vec[..]);
+
+    assert_eq!(row.transpose() * row, na::outer(&vec, &vec))
+}