qcr/gtsam-quadrics

dC_dx problem

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Wang-Minxin commented

Hi. In QuadricCamera.cpp， why the code "Eigen::Matrix<double, 16, 16> dXi_dX = -kron(Xi.transpose(), Xi); " has a negative sign.
In my opinion Xi = X.inverse(), so Xi = XiXXi , and then vec(Xi)=kron(Xi.transpose(),Xi)vec(X)