lcsim/src/org/lcsim/util/swim

diff -u -r1.4 -r1.5
--- Helix.java	20 Aug 2005 23:25:07 -0000	1.4
+++ Helix.java	22 Aug 2005 03:31:16 -0000	1.5
@@ -19,7 +19,7 @@

  * All quantities in this class are dimensionless. It has no dependencies
  * except for Hep3Vector (which could easily be removed).
  * @author tonyj

- * @version $Id: Helix.java,v 1.4 2005/08/20 23:25:07 tonyj Exp $

+ * @version $Id: Helix.java,v 1.5 2005/08/22 03:31:16 tonyj Exp $

  */
 public class Helix implements Trajectory
 {

@@ -64,7 +64,8 @@

    {
       double darg  = r*r/(2.*radius*radiusOfCenter) - radiusOfCenter/(2.*radius) - radius/(2.*radiusOfCenter);
       double diff  = asin(darg) + phi - phiToCenter;

-      return (radius/cosLambda)*diff;

+      if (diff < 0) diff += 2*Math.PI;
+      return (Math.abs(radius)/cosLambda)*diff;

    }
    
    /**

lcsim/src/org/lcsim/util/swim

diff -u -r1.4 -r1.5
--- HelixSwimmer.java	20 Aug 2005 23:25:07 -0000	1.4
+++ HelixSwimmer.java	22 Aug 2005 03:31:16 -0000	1.5
@@ -12,7 +12,7 @@

  * A simple helix smimmer for use in org.lcsim. Uses standard lcsim units
  * Tesla, mm, GeV. This swimmer works for charged and neutral tracks.
  * @author tonyj

- * @version $Id: HelixSwimmer.java,v 1.4 2005/08/20 23:25:07 tonyj Exp $

+ * @version $Id: HelixSwimmer.java,v 1.5 2005/08/22 03:31:16 tonyj Exp $

  */
 public class HelixSwimmer
 {

@@ -67,13 +67,25 @@

    }
    public Hep3Vector getPointAtDistance(double alpha)
    {

+      if (trajectory == null) throw new RuntimeException("Trajectory not set");

       return trajectory.getPointAtDistance(alpha);
    }

+   public double getDistanceToRadius(double r)
+   {
+      if (trajectory == null) throw new RuntimeException("Trajectory not set");
+      return trajectory.getDistanceToInfiniteCylinder(r);
+   }
+   public double getDistanceToZ(double z)
+   {
+      if (trajectory == null) throw new RuntimeException("Trajectory not set");
+      double result = trajectory.getDistanceToZPlane(z);
+      if (result<0) result = trajectory.getDistanceToZPlane(-z);
+      return result;
+   }

    public double getDistanceToCylinder(double r,double z)
    {

-      double x1 = trajectory.getDistanceToInfiniteCylinder(r);
-      double x2 = trajectory.getDistanceToZPlane(z);
-      if (x2<0) x2 = trajectory.getDistanceToZPlane(-z);

+      double x1 = getDistanceToRadius(r);
+      double x2 = getDistanceToZ(z);

       return Double.isNaN(x1) ? x2 : Math.min(x1,x2);
    }
 }

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