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From "J.Pietschmann" <j3322...@yahoo.de>
Subject [math] Exceptions again...
Date Fri, 26 Sep 2003 20:13:13 GMT
Hi,
I found that [math] still wont compile on JDK 1.3 due to the
super(throwable) constructors in MathException. Should we just write
off 1.3 users, now that a reasonable 1.4 is available on basically
all platforms which run Java at all?
Unless I'm mistaken, Brent's patch contained some corrections for
this problem.

Further, there still wasn't a conclusion on what to do with
analysis.ConvergenceException, which is used in util.ContinuedFraction
only, and also is a RuntimeException instead of a checked Exception.

Point one: given the current code, it seems to be misplaced.

Point two: Falling out of the loops in the root finders actually
indicates a convergence problem (either too stringent accuracy settings,
ill conditioned functions causing oscillations or a bug in the algorithm)
I'd like to use a ConvergenceException for this condition too, however,
throwing a mix of checked and unchecked exceptions for conditions of
comparable complexity is something I'd rather avoid.

Possible solutions:
1. abolish ConvergenceException completely and replace it in
  ContinuedFraction by a (checked) MathException. This will cause
  adding a "throws MathException" in a heck of a lot of places,
  including on gamma and beta functions and everywhere they are used.
  The discussion whether the kind of functions should throw a checked
  exception wans't conclusive yet.
2. derive ConvergenceException from MathException (and palce it in
  [math] root), further see above.
3. make MathException a runtime exception and replace
  ConvergenceException with a MathException.
4. make MathException a runtime exception and derive
   ConvergenceException from MathException.
5. Leave as is but move ConvergenceExcpetion to [math] root
6. as 5 but move to [math]/util

Any ideas/recomendations/votes?

J.Pietschmann


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