ss/bugfix-2024-08 #84
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Also updates derivative evaluation and adds option to normalize pbf model to peak value of 1 in the limit of low scattering.
Fix errors in the calculation of the (burst_width, dm) and (scattering_timescale, scattering_timescale) mixed partial derivative. Impacts the calculation of the analytical hessian for models with scattering.
Fixes bugs in the calculation of (burst_width, scattering_index), (scattering_index, scattering_index), and (dm, dm_index). Unlikely to impact results since we do not usually fit for the dm_index or scattering_index.
Only changes partial derivatives with respect to the scattering index, which is usually not fit.
emmanuelfonseca
approved these changes
Sep 26, 2024
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This builds on the bugfix-2024-01 branch. The primary change involves using the scaled complimentary error function instead of the error function when calculating the PBF model. This avoids problems with numerical overflow previously observed when the scattering time becomes small relative to the burst width. Before, in order to mitigate these numerical issues, we switched to using a Gaussian model for the time profile when the scattering timescale dropped below some threshold. However, due to differing normalizations between the Gaussian and PBF model, this introduced a step-like feature in the burst spectrum. Now, we are able to evaluate the PBF model directly for all scattering timescales.
Also fixes (copy-paste) errors in the calculation of the (burst_width, dm), (scattering_timescale, scattering_timescale), (burst_width, scattering_index), (scattering_index, scattering_index), and (dm, dm_index) mixed partial derivative. This will impact the calculation of the analytical hessian, and hence parameter uncertainties, for models with scattering.