From 375f310e2d81ec0c006d5858e181b1f8b7029345 Mon Sep 17 00:00:00 2001 From: Ken MacDonald Date: Thu, 19 Sep 2024 13:49:17 -0400 Subject: [PATCH] Updating the documentation for ramp fitting wrt the likelihood algorithm. --- docs/stcal/ramp_fitting/description.rst | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/docs/stcal/ramp_fitting/description.rst b/docs/stcal/ramp_fitting/description.rst index ea635b1b..49f0dd0b 100644 --- a/docs/stcal/ramp_fitting/description.rst +++ b/docs/stcal/ramp_fitting/description.rst @@ -19,8 +19,9 @@ using the array-based functionality of numpy. The size of the block depends on the image size and the number of groups. -There is also a likelihood algorithm implementing an algorithm based on the group -differences of a ramp. See the detailed description below. +There is also a new algorithm available for testing, the likelihood +algorithm, implementing an algorithm based on the group differences +of a ramp. See :ref:`likelihood algorithm `. .. _ramp_output_products: @@ -320,6 +321,8 @@ that pixel will be flagged as JUMP_DET in the corresponding integration in the "rateints" product. That pixel will also be flagged as JUMP_DET in the "rate" product. +.. _likelihood_algo: + Likelihood Algorithm Details ---------------------------- As an alternative to the OLS algorithm, a likelihood algorithm can be selected @@ -348,11 +351,9 @@ The covariance matrix :math:`C` is a tridiagonal matrix, due to the nature of th differences. Because the covariance matrix is tridiagonal, the computational complexity reduces from :math:`O(n^3)` to :math:`O(n)`. To see the detailed derivation and computations implemented, refer to the links above. -The Poisson and read noise computations are based on equations (27) and (28), -in the first link below, defining :math:`\alpha_i`, the diagonal of :math:`C`, -and :math:`\beta_i`, the off diagonal. - -The full details of the algorithm can be found here: +The Poisson and read noise computations are based on equations (27) and (28), in `Brandt (2024) `__ -and + +For more details, especially for the jump detection portion in the liklihood +algorithm, see `Brandt (2024) `__.