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https://issues.apache.org/jira/browse/GEOMETRY-146?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17527268#comment-17527268
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Matt Juntunen commented on GEOMETRY-146:
----------------------------------------
{{neighborEntriesFullBaseline}} was a baseline comparison method that simply
iterated through the _entire_ map and pulled out the ones that were within the
max distance. It was basically like this:
{code:java}
Vector3D refPt = ...
double maxDist = ...
List<Entry<Vector3D, Integer>> neighbors = new ArrayList<>();
for (Entry<Vector3D, Integer> entry : map.entrySet()) {
if (entry.getKey().distance(refPt) <= maxDist) {
neighbors.add(entry);
}
}
{code}
No optimizations or anything. I was completely dumbfounded that this was faster
than anything else but I was unable to see anything wrong with the tests. The
tests above are with maps with about ~8000 entries. The main culprit I could
see was the use of streams vs raw iterators. For example, {{neighborEntries}}
and {{neighborEntriesFullStreamBaseline}} use streams.
> PointSet/Map closest points
> ---------------------------
>
> Key: GEOMETRY-146
> URL: https://issues.apache.org/jira/browse/GEOMETRY-146
> Project: Commons Geometry
> Issue Type: New Feature
> Reporter: Matt Juntunen
> Priority: Major
> Fix For: 1.1
>
>
> Add methods to the new {{PointSet}} and {{PointMap}} interfaces to allow
> querying of points in order of distance from a query point.
> {code:java}
> PointSet<P> {
> // find the closest point to pt or null if empty
> P closest(P pt);
> // iterate through points in order, with points closest to pt coming first
> Iterable<P> closestFirst(P pt);
> // find the farthest point from pt or null if emtpy
> P farthest(P pt);
> // iterate through point in order, with points farthest from pt coming
> first
> Iterable<P> farthestFirst(P pt);
> }
> {code}
> {{PointMap}} should have similar methods providing access to the map keys and
> entries.
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