fix(ode): corrector equation using update instead of y-y_predict - #3285
Open
bcaddy wants to merge 1 commit into
Open
fix(ode): corrector equation using update instead of y-y_predict#3285bcaddy wants to merge 1 commit into
bcaddy wants to merge 1 commit into
Conversation
The correction d = y - y_predict must be the full distance between the Newton iterate and the predictor, so it is recomputed from y on every evaluation. It cannot be read from the Newton solver's update vector: that only holds the last Newton step, not the accumulated correction, which would change the root of the residual to 0 = psi - c * f(t+dt, y). Also includes a regression test for this bug Assisted-by: Claude:fable-5 Signed-off-by: Robert Caddy <rcaddy@princeton.edu>
This file contains hidden or 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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
The correction d = y - y_predict must be the full distance between the Newton iterate and the predictor, so it is recomputed from y on every evaluation. It cannot be read from the Newton solver's update vector: that only holds the last Newton step, not the accumulated correction, which would change the root of the residual to 0 = psi - c * f(t+dt, y).
Also includes a regression test for this bug
Assisted-by: Claude:fable-5