fix bug on computation of SO(3) logmap

when theta near 0 (or 2pi, 4pi...)
2021-06-01 09:38:42 -04:00 · 2021-06-01 09:38:42 -04:00 · 4ef43387bd
parent d5dbaf7ce7
commit 4ef43387bd
1 changed files with 2 additions and 1 deletions
--- a/gtsam/geometry/SO3.cpp
+++ b/gtsam/geometry/SO3.cpp
@ -278,7 +278,8 @@ Vector3 SO3::Logmap(const SO3& Q, ChartJacobian H) {
    } else {
      // when theta near 0, +-2pi, +-4pi, etc. (trace near 3.0)
      // use Taylor expansion: theta \approx 1/2-(t-3)/12 + O((t-3)^2)
-      magnitude = 0.5 - tr_3 * tr_3 / 12.0;
+      // see https://github.com/borglab/gtsam/issues/746 for details
+      magnitude = 0.5 - tr_3 / 12.0;
    }
    omega = magnitude * Vector3(R32 - R23, R13 - R31, R21 - R12);
  }