From b5f64fe1b46ee907960896306c561b0d692ad8a4 Mon Sep 17 00:00:00 2001 From: dellaert Date: Wed, 3 Dec 2014 21:12:03 +0100 Subject: [PATCH] Fixed types - Thanks @mikebosse --- GTSAM-Concepts.md | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/GTSAM-Concepts.md b/GTSAM-Concepts.md index 469659661..3e390fda6 100644 --- a/GTSAM-Concepts.md +++ b/GTSAM-Concepts.md @@ -44,7 +44,7 @@ A given chart is implemented using a small class that defines the chart itself ( For many differential manifolds, an obvious mapping is the `exponential map`, which associates staright lines in the tangent space with geodesics on the manifold (and it's inverse, the log map). However, there are two cases in which we deviate from this: - * Sometimes, most notably for *SO(3)* and *SE(3)*, the exponential map is unnecessarily expensive for use in optimiazation. Hence, the `defaultChart` functor returns a chart that is much cheaper to evaluate. + * Sometimes, most notably for *SO(3)* and *SE(3)*, the exponential map is unnecessarily expensive for use in optimization. Hence, the `defaultChart` functor returns a chart that is much cheaper to evaluate. * While vector spaces (see below) are in principle also manifolds, it is overkill to think about charts etc. Really, we should simply think about vector addition and subtraction. Hence, while a `defaultChart` functor is defined by default for every vector space, GTSAM will never call it. @@ -132,7 +132,7 @@ The conventions for `gtsam::traits` are as follows: Point2 p_; retract(const Point2& p) : p_(p) {} Point2 operator()(const Vector2& v) { - return Point2(p.x()+v[0], p.y()+v[1]); + return Point2(p_.x()+v[0], p_.y()+v[1]); } } @@ -274,7 +274,7 @@ Providing the Vector space concept is easier: and - Point2 inverse(const Point2& p) { return p.transpose();} + Point2 inverse(const Point2& p) { return -p;} Point2 operator+(const Point2& p, const Point2& q) { return p+q;} Point2 compose(const Point2& p, const Point2& q) { return p+q;} Point2 between(const Point2& p, const Point2& q) { return q-p;}