From 4d24f2af806511d65fa893fed8438308211c77dc Mon Sep 17 00:00:00 2001 From: Richard Roberts Date: Sun, 4 Sep 2011 15:34:28 +0000 Subject: [PATCH] Improving HessianFactor documentation --- gtsam/linear/HessianFactor.h | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/gtsam/linear/HessianFactor.h b/gtsam/linear/HessianFactor.h index 44e810e22..d5f35c9b2 100644 --- a/gtsam/linear/HessianFactor.h +++ b/gtsam/linear/HessianFactor.h @@ -52,9 +52,16 @@ namespace gtsam { /** * A general quadratic factor of the form * f(x) = x'Hx + hx + c - * and stores the matrix H, the vector h, and the constant term c. This factor - * is one of the factors that can be in a GaussianFactorGraph. It may - * be returned from NonlinearFactor::linearize(), but is also + * and stores the matrix H, the vector h, and the constant term c. + * + * When H is positive semidefinite, this factor represents a Gaussian, + * in which case H is the information + * matrix \Lambda, which is the inverse of the covariance matrix \Sigma, + * h is the information vector \eta = \Lambda \mu, and c is the error + * at the mean, when x = \mu. + * + * This factor is one of the factors that can be in a GaussianFactorGraph. + * It may be returned from NonlinearFactor::linearize(), but is also * used internally to store the Hessian during Cholesky elimination. * * This can represent a quadratic factor with characteristics that cannot be