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https://issues.apache.org/jira/browse/GEOMETRY-146?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17526158#comment-17526158
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Matt Juntunen commented on GEOMETRY-146:
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It turns out that my instincts on the performance of {{neighborEntries}} were
incorrect and I am not able to find a performance boost over just using
{{nearToFar}} or even just iterating through the entire map. Below are the JMH
results for the best implementation I could come up with.
||Benchmark||(dist)||(randomSeed)||(shape)||Mode||Cnt||Score||Error||Units||
|neighborEntries|random|1|block|avgt|5|18078272.739|± 2855877.430|ns/op|
|neighborEntriesFullBaseline|random|1|block|avgt|5|3953413.160|±
1299435.732|ns/op|
|neighborEntriesFullStreamBaseline|random|1|block|avgt|5|19190180.574|±
3775274.018|ns/op|
|neighborEntriesNearToFarBaseline|random|1|block|avgt|5|13143387.077|±
2344194.490|ns/op|
|neighborEntryIterable|random|1|block|avgt|5|15025352.786|± 3978281.128|ns/op|
- {{neighborEntries}} - supposedly "optimized" method
- {{neighborEntriesFullBaseline}} - iterating through the entire map and
checking the distance for each entry
- {{neighborEntriesFullStreamBaseline}} - filtering a stream over the map entry
set
- {{neighborEntriesNearToFarBaseline}} - iterating over the {{nearToFar}}
collection and breaking out of the loop when the max distance is passed
- {{neighborEntryIterable}} - iterator version of {{neighborEntries}}
Based on these results, I'm going to remove {{neighborEntries}} from the API.
There isn't a performance boost and the functionality can be implemented in
terms of the other methods.
> 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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