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https://issues.apache.org/jira/browse/NUMBERS-163?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17366760#comment-17366760
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Alex Herbert commented on NUMBERS-163:
--------------------------------------
I think that allowing the addition of a BigDecimal in the API would have
problems ensuring accuracy. Either you convert the BigDecimal to a double (loss
of precision) or you convert it to a series of overlapping double values and
add each one. This will be slow.
Untested...
{code:java}
// Addend
BigDecimal x;
if (x.abs().compareTo(new BigDecimal(Double.MAX_VALUE)) > 0) {
// Throw or just make the sum infinity
throw new IllegalArgumentException("Too big");
}
while (true) {
double d = x.toDouble();
if (d == 0) {
// Because BigDecimal can be below Double.MIN_VALUE
break;
}
// Add the double d to our sum
// Get the rest of the number
x = x.subtract(new BigDecimal(d));
}
{code}
Do you want to support this?
> 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: 1h 20m
> 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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