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https://issues.apache.org/jira/browse/NUMBERS-163?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17365006#comment-17365006
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Gilles Sadowski commented on NUMBERS-163:
-----------------------------------------
Attached
* "FMA.java" (additional factory method)
* "Sum.java"
To prevent API bloat in the upcoming release, we should remove the
{{LinearCombination}} and {{Summation}} classes given that they are syntactic
sugar for the more versatile {{FMA}} class (name TBD if "FMA" is confusing).
I wouldn't add {{Sum}} for the same reason (and because of its "mixed bag"
feeling of addition and product).
Those now seem fairly application-dependent. E.g. one may need
{code:java}
public double linearCombination(double[] a, double[] b) { /* ... */ }
{code}
while another would rather have
{code:java}
public double scalarProduct(Vector3D a, Vector3D b) { /* ... */ }
{code}
There are no failures with {{SumTest}} (using {{Sum}} as implemented in the
attached file); but I didn't check that all cases were covered by that test
suite. IOW, if you agree with the above, a review of {{FMA}} is necessary and a
test suite yet to be written...
> Summation and LinearCombination Accumulators
> --------------------------------------------
>
> Key: NUMBERS-163
> URL: https://issues.apache.org/jira/browse/NUMBERS-163
> Project: Commons Numbers
> Issue Type: New Feature
> Reporter: Matt Juntunen
> Priority: Major
> Attachments: FMA.java, Sum.java
>
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> It would be useful to have simple accumulator classes in {{Summation}} and
> {{LinearCombination}} to perform extended precision operations on arbitrary
> collections of values without requiring conversion to {{double[]}}. Ex:
> {code:java}
> Summation.Accumulator sum= Summation.accumulator(1d);
> sum.add(x)
> .add(y)
> .add(z)
> .add(w);
> double sumResult = sum.get();
> LinearCombination.Accumulator comb = LinearCombination.accumulator(1d);
> comb.add(x, scale)
> .add(y, scale)
> .add(z, scale)
> .add(w, scale);
> double combResult = comb.get();
> {code}
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