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Posted to commits@lucene.apache.org by kw...@apache.org on 2017/12/13 12:16:04 UTC

lucene-solr:branch_7x: LUCENE-8095: Improve javadocs for circle constructors, and rename some variables.

Repository: lucene-solr
Updated Branches:
  refs/heads/branch_7x b2049d4ad -> 473e38813


LUCENE-8095: Improve javadocs for circle constructors, and rename some variables.


Project: http://git-wip-us.apache.org/repos/asf/lucene-solr/repo
Commit: http://git-wip-us.apache.org/repos/asf/lucene-solr/commit/473e3881
Tree: http://git-wip-us.apache.org/repos/asf/lucene-solr/tree/473e3881
Diff: http://git-wip-us.apache.org/repos/asf/lucene-solr/diff/473e3881

Branch: refs/heads/branch_7x
Commit: 473e38813ef5ef895f9490bc2ef87081e2485ec2
Parents: b2049d4
Author: Karl Wright <Da...@gmail.com>
Authored: Wed Dec 13 07:09:46 2017 -0500
Committer: Karl Wright <Da...@gmail.com>
Committed: Wed Dec 13 07:15:58 2017 -0500

----------------------------------------------------------------------
 .../lucene/spatial3d/geom/GeoCircleFactory.java | 29 ++++++++---
 .../lucene/spatial3d/geom/GeoExactCircle.java   | 55 +++++++++++---------
 .../spatial3d/geom/GeoStandardCircle.java       |  4 +-
 3 files changed, 53 insertions(+), 35 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/lucene-solr/blob/473e3881/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoCircleFactory.java
----------------------------------------------------------------------
diff --git a/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoCircleFactory.java b/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoCircleFactory.java
index 8feecce..f32f366 100644
--- a/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoCircleFactory.java
+++ b/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoCircleFactory.java
@@ -26,27 +26,40 @@ public class GeoCircleFactory {
   }
 
   /**
-   * Create a GeoCircle of the right kind given the specified bounds.
+   * Create a GeoCircle from a center and a cutoff angle. The resulting shape is a circle in spherical
+   * planets, otherwise is an ellipse. It is the most efficient shape to represent a circle on a sphere.
+   *
    * @param planetModel is the planet model.
    * @param latitude is the center latitude.
    * @param longitude is the center longitude.
-   * @param radius is the radius angle.
+   * @param cutoffAngle is the cutoff angle.
    * @return a GeoCircle corresponding to what was specified.
    */
-  public static GeoCircle makeGeoCircle(final PlanetModel planetModel, final double latitude, final double longitude, final double radius) {
-    if (radius < Vector.MINIMUM_ANGULAR_RESOLUTION) {
+  public static GeoCircle makeGeoCircle(final PlanetModel planetModel, final double latitude, final double longitude, final double cutoffAngle) {
+    if (cutoffAngle < Vector.MINIMUM_ANGULAR_RESOLUTION) {
       return new GeoDegeneratePoint(planetModel, latitude, longitude);
     }
-    return new GeoStandardCircle(planetModel, latitude, longitude, radius);
+    return new GeoStandardCircle(planetModel, latitude, longitude, cutoffAngle);
   }
 
-  /** Create an exact GeoCircle given specified bounds and desired accuracy.
+  /**
+   * Create an GeoCircle from a center, a radius and a desired accuracy. It is the most accurate shape to represent
+   * a circle in non-spherical planets.
+   * <p>
+   * The accuracy of the circle is defined as the maximum linear distance between any point on the
+   * surface circle and planes that describe the circle. Therefore, with planet model WSG84, since the
+   * radius of earth is 6,371,000 meters, an accuracy of 1e-6 corresponds to 6.3 meters.
+   * For an accuracy of 1.0 meters, the accuracy value would be 1.6e-7. The maximum accuracy possible is 1e-12.
+   * <p>
+   * Note that this method may thrown an IllegalArgumentException if the circle being specified cannot be
+   * represented by plane approximation given the planet model provided.
+   *
    * @param planetModel is the planet model.
    * @param latitude is the center latitude.
    * @param longitude is the center longitude.
    * @param radius is the radius surface distance.
-   * @param accuracy is the maximum linear distance between the circle approximation and the real circle, as computed using
-   *  the Vincenty formula.
+   * @param accuracy is the maximum linear distance between the circle approximation and the real circle,
+   *                 as computed using the Vincenty formula.
    * @return a GeoCircle corresponding to what was specified.
    */
   public static GeoCircle makeExactGeoCircle(final PlanetModel planetModel, final double latitude, final double longitude, final double radius, final double accuracy) {

http://git-wip-us.apache.org/repos/asf/lucene-solr/blob/473e3881/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoExactCircle.java
----------------------------------------------------------------------
diff --git a/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoExactCircle.java b/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoExactCircle.java
index 876b24f..845dd6a 100644
--- a/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoExactCircle.java
+++ b/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoExactCircle.java
@@ -24,44 +24,47 @@ import java.io.InputStream;
 import java.io.OutputStream;
 
 /**
- * Circular area with a center and radius.
+ * Circular area with a center and a radius that represents the surface distance to the center.
+ * The circle is divided in sectors where the circle edge is approximated using Vincenty formulae.
+ * The higher is the precision the more sectors are needed to describe the shape and therefore a penalty
+ * in performance.
  *
  * @lucene.experimental
  */
 class GeoExactCircle extends GeoBaseCircle {
   /** Center of circle */
   protected final GeoPoint center;
-  /** Cutoff angle of circle (not quite the same thing as radius) */
-  protected final double cutoffAngle;
+  /** Radius of circle */
+  protected final double radius;
   /** Actual accuracy */
   protected final double actualAccuracy;
-  /** A point that is on the world and on the circle plane */
+  /** A point that is on the edge of the circle */
   protected final GeoPoint[] edgePoints;
-  /** Slices of the circle. */
+  /** Slices of the circle */
   protected final List<CircleSlice> circleSlices;
 
   /** Constructor.
    *@param planetModel is the planet model.
    *@param lat is the center latitude.
    *@param lon is the center longitude.
-   *@param cutoffAngle is the surface radius for the circle.
-   *@param accuracy is the allowed error value (linear distance).
+   *@param radius is the surface radius for the circle.
+   *@param accuracy is the allowed error value (linear distance). Maximum accuracy is 1e-12.
    */
-  public GeoExactCircle(final PlanetModel planetModel, final double lat, final double lon, final double cutoffAngle, final double accuracy) {
+  public GeoExactCircle(final PlanetModel planetModel, final double lat, final double lon, final double radius, final double accuracy) {
     super(planetModel);
     if (lat < -Math.PI * 0.5 || lat > Math.PI * 0.5)
       throw new IllegalArgumentException("Latitude out of bounds");
     if (lon < -Math.PI || lon > Math.PI)
       throw new IllegalArgumentException("Longitude out of bounds");
-    if (cutoffAngle < 0.0)
-      throw new IllegalArgumentException("Cutoff angle out of bounds");
-    if (cutoffAngle < Vector.MINIMUM_RESOLUTION)
-      throw new IllegalArgumentException("Cutoff angle cannot be effectively zero");
-    if (planetModel.minimumPoleDistance - cutoffAngle  < Vector.MINIMUM_RESOLUTION)
-      throw new IllegalArgumentException("Cutoff angle out of bounds. It cannot be bigger than " +  planetModel.minimumPoleDistance + " for this planet model");
+    if (radius < 0.0)
+      throw new IllegalArgumentException("Radius out of bounds");
+    if (radius < Vector.MINIMUM_RESOLUTION)
+      throw new IllegalArgumentException("Radius cannot be effectively zero");
+    if (planetModel.minimumPoleDistance - radius < Vector.MINIMUM_RESOLUTION)
+      throw new IllegalArgumentException("Radius out of bounds. It cannot be bigger than " +  planetModel.minimumPoleDistance + " for this planet model");
 
     this.center = new GeoPoint(planetModel, lat, lon);
-    this.cutoffAngle = cutoffAngle;
+    this.radius = radius;
 
     if (accuracy < Vector.MINIMUM_RESOLUTION) {
       actualAccuracy = Vector.MINIMUM_RESOLUTION;
@@ -72,10 +75,10 @@ class GeoExactCircle extends GeoBaseCircle {
     // We construct approximation planes until we have a low enough error estimate
     final List<ApproximationSlice> slices = new ArrayList<>(100);
     // Construct four cardinal points, and then we'll build the first two planes
-    final GeoPoint northPoint = planetModel.surfacePointOnBearing(center, cutoffAngle, 0.0);
-    final GeoPoint southPoint = planetModel.surfacePointOnBearing(center, cutoffAngle, Math.PI);
-    final GeoPoint eastPoint = planetModel.surfacePointOnBearing(center, cutoffAngle, Math.PI * 0.5);
-    final GeoPoint westPoint = planetModel.surfacePointOnBearing(center, cutoffAngle, Math.PI * 1.5);
+    final GeoPoint northPoint = planetModel.surfacePointOnBearing(center, radius, 0.0);
+    final GeoPoint southPoint = planetModel.surfacePointOnBearing(center, radius, Math.PI);
+    final GeoPoint eastPoint = planetModel.surfacePointOnBearing(center, radius, Math.PI * 0.5);
+    final GeoPoint westPoint = planetModel.surfacePointOnBearing(center, radius, Math.PI * 1.5);
 
     final GeoPoint edgePoint;
     if (planetModel.c > planetModel.ab) {
@@ -101,9 +104,9 @@ class GeoExactCircle extends GeoBaseCircle {
       // To do this, we need to look at the part of the circle that will have the greatest error.
       // We will need to compute bearing points for these.
       final double interpPoint1Bearing = (thisSlice.point1Bearing + thisSlice.middlePointBearing) * 0.5;
-      final GeoPoint interpPoint1 = planetModel.surfacePointOnBearing(center, cutoffAngle, interpPoint1Bearing);
+      final GeoPoint interpPoint1 = planetModel.surfacePointOnBearing(center, radius, interpPoint1Bearing);
       final double interpPoint2Bearing = (thisSlice.point2Bearing + thisSlice.middlePointBearing) * 0.5;
-      final GeoPoint interpPoint2 = planetModel.surfacePointOnBearing(center, cutoffAngle, interpPoint2Bearing);
+      final GeoPoint interpPoint2 = planetModel.surfacePointOnBearing(center, radius, interpPoint2Bearing);
       
       // Is this point on the plane? (that is, is the approximation good enough?)
       if (!thisSlice.mustSplit && Math.abs(thisSlice.plane.evaluate(interpPoint1)) < actualAccuracy && Math.abs(thisSlice.plane.evaluate(interpPoint2)) < actualAccuracy) {
@@ -145,13 +148,13 @@ class GeoExactCircle extends GeoBaseCircle {
   public void write(final OutputStream outputStream) throws IOException {
     SerializableObject.writeDouble(outputStream, center.getLatitude());
     SerializableObject.writeDouble(outputStream, center.getLongitude());
-    SerializableObject.writeDouble(outputStream, cutoffAngle);
+    SerializableObject.writeDouble(outputStream, radius);
     SerializableObject.writeDouble(outputStream, actualAccuracy);
   }
 
   @Override
   public double getRadius() {
-    return cutoffAngle;
+    return radius;
   }
 
   @Override
@@ -235,14 +238,14 @@ class GeoExactCircle extends GeoBaseCircle {
     if (!(o instanceof GeoExactCircle))
       return false;
     GeoExactCircle other = (GeoExactCircle) o;
-    return super.equals(other) && other.center.equals(center) && other.cutoffAngle == cutoffAngle && other.actualAccuracy == actualAccuracy;
+    return super.equals(other) && other.center.equals(center) && other.radius == radius && other.actualAccuracy == actualAccuracy;
   }
 
   @Override
   public int hashCode() {
     int result = super.hashCode();
     result = 31 * result + center.hashCode();
-    long temp = Double.doubleToLongBits(cutoffAngle);
+    long temp = Double.doubleToLongBits(radius);
     result = 31 * result + (int) (temp ^ (temp >>> 32));
     temp = Double.doubleToLongBits(actualAccuracy);
     result = 31 * result + (int) (temp ^ (temp >>> 32));    
@@ -251,7 +254,7 @@ class GeoExactCircle extends GeoBaseCircle {
 
   @Override
   public String toString() {
-    return "GeoExactCircle: {planetmodel=" + planetModel+", center=" + center + ", radius=" + cutoffAngle + "(" + cutoffAngle * 180.0 / Math.PI + "), accuracy=" + actualAccuracy + "}";
+    return "GeoExactCircle: {planetmodel=" + planetModel+", center=" + center + ", radius=" + radius + "(" + radius * 180.0 / Math.PI + "), accuracy=" + actualAccuracy + "}";
   }
   
   /** A temporary description of a section of circle.

http://git-wip-us.apache.org/repos/asf/lucene-solr/blob/473e3881/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoStandardCircle.java
----------------------------------------------------------------------
diff --git a/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoStandardCircle.java b/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoStandardCircle.java
index acba9f5..7ac45932 100755
--- a/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoStandardCircle.java
+++ b/lucene/spatial3d/src/java/org/apache/lucene/spatial3d/geom/GeoStandardCircle.java
@@ -21,7 +21,9 @@ import java.io.OutputStream;
 import java.io.IOException;
 
 /**
- * Circular area with a center and radius.
+ * Circular area with a center and cutoff angle that represents the latitude and longitude distance
+ * from the center where the planet will be cut. The resulting area is a circle for spherical
+ * planets and an ellipse otherwise.
  *
  * @lucene.experimental
  */