diff --git a/doc/source/users/user_manual/likelihood.rst b/doc/source/users/user_manual/likelihood.rst index 6d32ee5..596cc7e 100755 --- a/doc/source/users/user_manual/likelihood.rst +++ b/doc/source/users/user_manual/likelihood.rst @@ -179,7 +179,7 @@ Levenberg-Marquardt algorithm ctools uses an iterative Levenberg-Marquardt algorithm for maximum likelihood estimation. Since the Levenberg-Marquardt algorithm minimises a function, we use :math:`-\ln L(M)` as the function to minimse. The Levenberg-Marquardt -algorithm starts with an inital guess of the :ref:`model ` parameters +algorithm starts with an initial guess of the :ref:`model ` parameters :math:`a_k` and iteratively replaces this estimate by a new estimate :math:`a_k + \Delta a_k`. The :math:`\Delta a_k` are determined by solving @@ -191,12 +191,12 @@ where .. math:: \alpha_{kl} = \frac{\partial^2 (-\ln L(M))}{\partial a_k \partial a_l} -is the curvature matrix +is the curvature matrix, .. math:: \beta_k = \frac{\partial (-\ln L(M))}{\partial a_k} -is the gradient and +is the gradient, and :math:`\delta_{kl}` is the Kronecker delta that is :math:`1` for :math:`k=l` and :math:`0` otherwise. :math:`\lambda` is a damping parameter that initially is set to 0.001. If a Levenberg-Marquardt iteration leads to @@ -247,8 +247,8 @@ where :math:`\ln L(M_s+M_b)` is the log-likelihood value obtained when fitting the source and the background together to the data, and :math:`\ln L(M_b)` is the log-likelihood value obtained when fitting only the background model to the data. -Under the hypothesis that the model :math:`M_b` provides a satisfactory fit -of the data, :math:`TS` follows a :math:`\chi^2_n` distribution with +Under the hypothesis that the model :math:`M_s+M_b` provides a satisfactory fit +of the data, :math:`\mathrm{TS}` follows a :math:`\chi^2_n` distribution with :math:`n` degrees of freedom, where :math:`n` is the number of free parameters in the source model component. Therefore @@ -256,9 +256,9 @@ in the source model component. Therefore p = \int_\mathrm{TS}^{+\infty} \chi^2_n(x) \:\: \mathrm{d}x gives the chance probability (p-value) that the log-likelihood improves by -:math:`TS/2` when adding the source model :math:`M_s` due to statistical +:math:`\mathrm{TS}/2` when adding the source model :math:`M_s` due to statistical fluctuations only. For :math:`n=1` the significance in Gaussian sigma -is given by :math:`\sqrt{TS}`. +is given by :math:`\sqrt{\mathrm{TS}}`. Upper flux limits