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author | Aleksandar Prokopec <axel22@gmail.com> | 2012-10-03 18:06:39 +0200 |
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committer | Aleksandar Prokopec <axel22@gmail.com> | 2012-10-04 11:32:27 +0200 |
commit | b405a2969477f9e9a76274eac1ebda3c0f2942ad (patch) | |
tree | 067747051a075740b041b665271032cfb31eb577 /src/library/scala/collection/parallel | |
parent | 3ffc62b49914c6bf466f0f5e10c8f34b2cff5899 (diff) | |
download | scala-b405a2969477f9e9a76274eac1ebda3c0f2942ad.tar.gz scala-b405a2969477f9e9a76274eac1ebda3c0f2942ad.tar.bz2 scala-b405a2969477f9e9a76274eac1ebda3c0f2942ad.zip |
SI-6467: Zero element in aggregate now by-name
Diffstat (limited to 'src/library/scala/collection/parallel')
-rw-r--r-- | src/library/scala/collection/parallel/ParIterableLike.scala | 11 | ||||
-rw-r--r-- | src/library/scala/collection/parallel/mutable/ParArray.scala | 2 |
2 files changed, 7 insertions, 6 deletions
diff --git a/src/library/scala/collection/parallel/ParIterableLike.scala b/src/library/scala/collection/parallel/ParIterableLike.scala index b9a9e35574..0c0ff2b027 100644 --- a/src/library/scala/collection/parallel/ParIterableLike.scala +++ b/src/library/scala/collection/parallel/ParIterableLike.scala @@ -433,12 +433,13 @@ self: ParIterableLike[T, Repr, Sequential] => * @tparam S the type of accumulated results * @param z the initial value for the accumulated result of the partition - this * will typically be the neutral element for the `seqop` operator (e.g. - * `Nil` for list concatenation or `0` for summation) + * `Nil` for list concatenation or `0` for summation) and may be evaluated + * more than once * @param seqop an operator used to accumulate results within a partition * @param combop an associative operator used to combine results from different partitions */ - def aggregate[S](z: S)(seqop: (S, T) => S, combop: (S, S) => S): S = { - tasksupport.executeAndWaitResult(new Aggregate(z, seqop, combop, splitter)) + def aggregate[S](z: =>S)(seqop: (S, T) => S, combop: (S, S) => S): S = { + tasksupport.executeAndWaitResult(new Aggregate(() => z, seqop, combop, splitter)) } def foldLeft[S](z: S)(op: (S, T) => S): S = seq.foldLeft(z)(op) @@ -1006,10 +1007,10 @@ self: ParIterableLike[T, Repr, Sequential] => override def merge(that: Fold[U]) = result = op(result, that.result) } - protected[this] class Aggregate[S](z: S, seqop: (S, T) => S, combop: (S, S) => S, protected[this] val pit: IterableSplitter[T]) + protected[this] class Aggregate[S](z: () => S, seqop: (S, T) => S, combop: (S, S) => S, protected[this] val pit: IterableSplitter[T]) extends Accessor[S, Aggregate[S]] { @volatile var result: S = null.asInstanceOf[S] - def leaf(prevr: Option[S]) = result = pit.foldLeft(z)(seqop) + def leaf(prevr: Option[S]) = result = pit.foldLeft(z())(seqop) protected[this] def newSubtask(p: IterableSplitter[T]) = new Aggregate(z, seqop, combop, p) override def merge(that: Aggregate[S]) = result = combop(result, that.result) } diff --git a/src/library/scala/collection/parallel/mutable/ParArray.scala b/src/library/scala/collection/parallel/mutable/ParArray.scala index 56cc06f99e..deff9eda3b 100644 --- a/src/library/scala/collection/parallel/mutable/ParArray.scala +++ b/src/library/scala/collection/parallel/mutable/ParArray.scala @@ -181,7 +181,7 @@ self => override def fold[U >: T](z: U)(op: (U, U) => U): U = foldLeft[U](z)(op) - override def aggregate[S](z: S)(seqop: (S, T) => S, combop: (S, S) => S): S = foldLeft[S](z)(seqop) + override def aggregate[S](z: =>S)(seqop: (S, T) => S, combop: (S, S) => S): S = foldLeft[S](z)(seqop) override def sum[U >: T](implicit num: Numeric[U]): U = { var s = sum_quick(num, arr, until, i, num.zero) |