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https://issues.apache.org/jira/browse/MATH-349?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12843047#action_12843047
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Phil Steitz edited comment on MATH-349 at 3/9/10 1:47 PM:
----------------------------------------------------------
Issue (2) in the bug description remains open. I think we should leave this
issue open until we have a solution for this. As stated above, I can see two
ways to fix this:
a) modify the normal approximation implementation so that it does not change
the parameters of z
b) eliminate pluggability of z (i.e., deprecate and then remove the constructor
that accepts a normal instance as a parameter)
a) could be accomplished in 2.x, but it would complicate the code and could be
bad for numerics. My vote is for b) - add a warning (about safety as well as
deprecation), deprecate now and if we get no complaints before 3.0, remove
then. Leave the issue open with fix version 3.0.
was (Author: psteitz):
Issue (2) in the bug description remains open. I think we should leave
this issue open until we have a solution for this. As stated above, I can see
two ways to fix this:
a) modify the normal approximation implementation so that it does not change
the parameters of z
b) eliminate pluggability of z (i.e., deprecate and then remove the constructor
that accepts a normal instance as a parameter)
a) could be accomplished in 2.x, but it would complicate the code and could be
bad for numerics. My vote is for b) - add a warning (about safety as well as
deprecation), deprecate now and if we get no complaints before 3.0, remove then.
> Dangerous code in "PoissonDistributionImpl"
> -------------------------------------------
>
> Key: MATH-349
> URL: https://issues.apache.org/jira/browse/MATH-349
> Project: Commons Math
> Issue Type: Bug
> Reporter: Gilles
> Priority: Minor
>
> In the following excerpt from class "PoissonDistributionImpl":
> {code:title=PoissonDistributionImpl.java|borderStyle=solid}
> public PoissonDistributionImpl(double p, NormalDistribution z) {
> super();
> setNormal(z);
> setMean(p);
> }
> {code}
> (1) Overridable methods are called within the constructor.
> (2) The reference "z" is stored and modified within the class.
> I've encountered problem (1) in several classes while working on issue 348.
> In those cases, in order to remove potential problems, I copied/pasted the
> body of the "setter" methods inside the constructor but I think that a more
> elegant solution would be to remove the "setters" altogether (i.e. make the
> classes immutable).
> Problem (2) can also create unexpected behaviour. Is it really necessary to
> pass the "NormalDistribution" object; can't it be always created within the
> class?
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