[
https://issues.apache.org/jira/browse/MATH-599?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13053321#comment-13053321
]
Phil Steitz commented on MATH-599:
----------------------------------
We use diffs to represent change to code. There are lots of reasons that diffs
are preferred to passing around files, which I will not repeat here.
The purpose of a diff for new files is that a) when the new file is part of a
larger patch, the diff can represent the entire change b) the diff is
guaranteed to be plain text c) the diff places the file in the right directory
location. Again, we use diffs to represent changes from a local checkout and
the svn repository. This enables us to unambiguously communicate changes or
proposed changes to the code.
That said, if contributors have a hard time creating diffs including new files
and committers are willing to work with zips / tars for new files, that is OK
too. The point is that diffs are better where possible.
> Re-implementation of Secant-based root finding algorithms
> ---------------------------------------------------------
>
> Key: MATH-599
> URL: https://issues.apache.org/jira/browse/MATH-599
> Project: Commons Math
> Issue Type: Improvement
> Reporter: Dennis Hendriks
> Labels: documentation, patch
> Fix For: 3.0
>
> Attachments: secant-based-root-finding-algos.patch
>
>
> Apache Commons Math currently has a SecantSolver. It is unclear exactly what
> algorithm this solver implements. It states: "The algorithm is modified to
> maintain bracketing of a root by successive approximations. Because of forced
> bracketing, convergence may be slower than the unrestricted Secant algorithm.
> However, this implementation should in general outperform the Regula Falsi
> method." The Regula Falsi method is exactly the Secant method modified to
> maintain a bracketed solution. It is therefore unclear what other
> modifications were done to make it 'better' than the Regula Falsi method.
> Besides the Secant and Regula Falsi methods, several other Secant-based
> root-finding algorithms exist, such as the the Illinois method, and the
> Pegasus method. All 4 are well-known, publisched algorithms.
> I created a patch, which changes the following:
> - Removed SecantSolver root-finding algorithm.
> - Implemented new Secant-based root-finding algorithms: SecantSolver,
> RegulaFalsiSolver, IllinoisSolver, and PegasusSolver.
> - Introduced BracketedSolution interface and AllowedSolutions enumeration,
> to control allowed solutions (under-approximations and over-approximations)
> for bracketed root-finding algorithms. Implemented for RegulaFalsiSolver,
> IllinoisSolver, and PegasusSolver.
> - Fixed documentation of BaseUnivariateRealSolver.solve methods, such that
> documentation order of arguments matches the order of the actual arguments.
> Note that the original SecantSolver was removed, and replaced by a
> root-finding algorithm that actually implements the Secant root-finding
> algorithm. As such, existing code using the SecantSolver is not backwards
> compatible. That is, even though the new SecantSolver does implement the same
> interfaces, the root-finding solutions may differ. In particular, the new
> SecantSolver does not maintain a bracketed solution, and does not guarantee
> convergence.
> I added unit tests, and I did a build, including checkstyle checking. I did
> not fix all checkstyle warnings though, as I consider some of them false
> positives.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
