Add Tukey loss function.
Change-Id: I7c76f13e01863440fc207e99b3fc7ad3fb6f7d1a
diff --git a/internal/ceres/loss_function.cc b/internal/ceres/loss_function.cc
index 62b545b..6500247 100644
--- a/internal/ceres/loss_function.cc
+++ b/internal/ceres/loss_function.cc
@@ -1,5 +1,5 @@
// Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2010, 2011, 2012 Google Inc. All rights reserved.
+// Copyright 2014 Google Inc. All rights reserved.
// http://code.google.com/p/ceres-solver/
//
// Redistribution and use in source and binary forms, with or without
@@ -114,6 +114,22 @@
}
}
+void TukeyLoss::Evaluate(double s, double* rho) const {
+ if (s <= a_squared_) {
+ // Inlier region.
+ const double value = 1.0 - s / a_squared_;
+ const double value_sq = value * value;
+ rho[0] = a_squared_ / 6.0 * (1.0 - value_sq * value);
+ rho[1] = 0.5 * value_sq;
+ rho[2] = -1.0 / a_squared_ * value;
+ } else {
+ // Outlier region.
+ rho[0] = a_squared_ / 6.0;
+ rho[1] = 0.0;
+ rho[2] = 0.0;
+ }
+}
+
ComposedLoss::ComposedLoss(const LossFunction* f, Ownership ownership_f,
const LossFunction* g, Ownership ownership_g)
: f_(CHECK_NOTNULL(f)),
