Return pointer to cached basis

gtsam/geometry/Unit3.cpp

@@ -58,7 +58,7 @@ Unit3 Unit3::Random(boost::mt19937 & rng) {
 }
 
 /* ************************************************************************* */
-Matrix Unit3::basis() const {
+const Matrix& Unit3::basis() const {
 
   // Return cached version if exists
   if (B_.rows() == 3)

gtsam/geometry/Unit3.h

@@ -84,7 +84,7 @@ public:
    * It is a 3*2 matrix [b1 b2] composed of two orthogonal directions
    * tangent to the sphere at the current direction.
    */
-  Matrix basis() const;
+  const Matrix& basis() const;
 
   /// Return skew-symmetric associated with 3D point on unit sphere
   Matrix skew() const;