From df296093a9aa60341ee50d41d039a3dc49f9685b Mon Sep 17 00:00:00 2001
From: Mike Barry <msb5014@gmail.com>
Date: Sun, 3 Nov 2024 05:50:11 -0500
Subject: [PATCH] add benchmark

---
 .../benchmarks/BenchmarkLoopLineMerge.java    | 81 +++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 planetiler-benchmarks/src/main/java/com/onthegomap/planetiler/benchmarks/BenchmarkLoopLineMerge.java

diff --git a/planetiler-benchmarks/src/main/java/com/onthegomap/planetiler/benchmarks/BenchmarkLoopLineMerge.java b/planetiler-benchmarks/src/main/java/com/onthegomap/planetiler/benchmarks/BenchmarkLoopLineMerge.java
new file mode 100644
index 0000000000..a003f8ca9b
--- /dev/null
+++ b/planetiler-benchmarks/src/main/java/com/onthegomap/planetiler/benchmarks/BenchmarkLoopLineMerge.java
@@ -0,0 +1,81 @@
+package com.onthegomap.planetiler.benchmarks;
+
+import com.onthegomap.planetiler.util.Format;
+import com.onthegomap.planetiler.util.LoopLineMerger;
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.function.Function;
+import org.locationtech.jts.geom.CoordinateXY;
+import org.locationtech.jts.geom.Geometry;
+import org.locationtech.jts.geom.GeometryFactory;
+import org.locationtech.jts.geom.LineString;
+import org.locationtech.jts.operation.linemerge.LineMerger;
+import org.locationtech.jts.util.GeometricShapeFactory;
+
+public class BenchmarkLoopLineMerge {
+
+  public static void main(String[] args) {
+    for (int i = 0; i < 10; i++) {
+      System.err.println(
+        " JTS line merger (/s):\t" +
+          timeJts(10) + "\t" +
+          timeJts(1_000) + "\t" +
+          timeJts(10_000) + "\t" +
+          timeJts(100_000));
+      System.err.println(
+        "loop line merger (/s):\t" +
+          timeLoop(10) + "\t" +
+          timeLoop(1_000) + "\t" +
+          timeLoop(10_000) + "\t" +
+          timeLoop(100_000));
+      System.err.println();
+    }
+  }
+
+  private static String timeLoop(int parts) {
+    return time(parts, geom -> {
+      var merger = new LoopLineMerger();
+      merger.add(geom);
+      return merger.getMergedLineStrings(0.1, 0.1);
+    });
+  }
+
+  private static String timeJts(int parts) {
+    return time(parts, geom -> {
+      var merger = new LineMerger();
+      merger.add(geom);
+      return merger.getMergedLineStrings();
+    });
+  }
+
+  private static String time(int parts, Function<Geometry, Collection<LineString>> fn) {
+    Geometry multiLinestring = makeCircles(parts);
+    long start = System.nanoTime();
+    long end = start + Duration.ofSeconds(1).toNanos();
+    int num = 0;
+    for (; System.nanoTime() < end;) {
+      fn.apply(multiLinestring);
+      num++;
+    }
+    return Format.defaultInstance()
+      .numeric(Math.round(num * 1d / ((System.nanoTime() - start) * 1d / Duration.ofSeconds(1).toNanos())), true);
+  }
+
+  private static Geometry makeCircles(int parts) {
+    var factory = new GeometricShapeFactory();
+    factory.setCentre(new CoordinateXY(0, 0));
+    factory.setSize(2);
+    factory.setNumPoints(parts);
+    List<LineString> lines = new ArrayList<>();
+    lines.add(factory.createArc(0, Math.PI * 2));
+    factory.setCentre(new CoordinateXY(1, 0));
+    lines.add(factory.createArc(0, Math.PI * 2));
+    factory.setCentre(new CoordinateXY(1, 1));
+    lines.add(factory.createArc(0, Math.PI * 2));
+    factory.setCentre(new CoordinateXY(0, 1));
+    lines.add(factory.createArc(0, Math.PI * 2));
+    return new GeometryFactory().createMultiLineString(lines.toArray(LineString[]::new));
+  }
+}