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https://issues.apache.org/jira/browse/MATH-387?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12889947#action_12889947
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Luc Maisonobe commented on MATH-387:
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>From my experience, convergence is more related to the problem to be solved
>than to the optimizer used.
> Duplicate code
> --------------
>
> Key: MATH-387
> URL: https://issues.apache.org/jira/browse/MATH-387
> Project: Commons Math
> Issue Type: Improvement
> Affects Versions: 2.1
> Reporter: Gilles
> Priority: Minor
> Fix For: 2.2
>
> Attachments: RealPointValuePair.java.diff
>
>
> In package optimization:
> {code:title=SimpleRealPointChecker.java|borderStyle=solid}
> public boolean converged(final int iteration, final RealPointValuePair
> previous, final RealPointValuePair current) {
> final double[] p = previous.getPoint();
> final double[] c = current.getPoint();
> for (int i = 0; i < p.length; ++i) {
> final double difference = Math.abs(p[i] - c[i]);
> final double size = Math.max(Math.abs(p[i]), Math.abs(c[i]));
> if ((difference > (size * relativeThreshold)) && (difference >
> absoluteThreshold)) {
> return false;
> }
> }
> return true;
> }
> {code}
> {code:title=SimpleVectorialPointChecker.java|borderStyle=solid}
> public boolean converged(final int iteration, final VectorialPointValuePair
> previous, final VectorialPointValuePair current) {
> final double[] p = previous.getPointRef();
> final double[] c = current.getPointRef();
> for (int i = 0; i < p.length; ++i) {
> final double pi = p[i];
> final double ci = c[i];
> final double difference = Math.abs(pi - ci);
> final double size = Math.max(Math.abs(pi), Math.abs(ci));
> if ((difference > (size * relativeThreshold)) &&
> (difference > absoluteThreshold)) {
> return false;
> }
> }
> return true;
> }
> {code}
> Do they do the same thing or am I missing something?
> Also in
> {code:title=SimpleScalarValueChecker.java|borderStyle=solid}
> public boolean converged(final int iteration, final RealPointValuePair
> previous, final RealPointValuePair current) {
> final double p = previous.getValue();
> final double c = current.getValue();
> final double difference = Math.abs(p - c);
> final double size = Math.max(Math.abs(p), Math.abs(c));
> return (difference <= (size * relativeThreshold)) || (difference <=
> absoluteThreshold);
> }
> {code}
> it seems overkill that one must create two {{RealPointValuePair}} objects
> when one just wants to compare two {{double}}. Shouldn't this class contain a
> method like
> {code}
> public boolean converged(int iteration, double previous, double current) {
> final double difference = Math.abs(previous - current);
> final double size = Math.max(Math.abs(previous), Math.abs(current));
> return (difference <= (size * relativeThreshold)) || (difference <=
> absoluteThreshold);
> {code}
> ?
> Also none of these methods seem to need an {{iteration}} parameter.
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