hps-java/src/main/java/org/lcsim/hps/users/phansson

diff -u -r1.1 -r1.2
--- WTrackUtils.java	9 Oct 2012 01:20:02 -0000	1.1
+++ WTrackUtils.java	23 Oct 2012 01:30:02 -0000	1.2
@@ -15,7 +15,7 @@

  * @author phansson
  */
 public class WTrackUtils {

-    boolean _debug = false;

+    private boolean _debug = false;

     List<Double> _delta_point =  new ArrayList<Double>();
     
     public WTrackUtils() {

@@ -28,6 +28,10 @@

     public void setDebug(boolean debug) {
         _debug = debug;
     }

+     
+    public boolean getDebug() {
+        return _debug;
+    }

     
     public List<Double> getDeltas() {
         return _delta_point;

@@ -59,31 +63,31 @@

          * Find the approximate path length to the point xp 
          * in arbitrary oriented, constant magnetic field with unit vector h
          */

-        if(_debug) {
-                System.out.println(this.getClass().getSimpleName() + ": getPathLengthToPlaneApprox ");
-                System.out.println(this.getClass().getSimpleName() + ": " + track.toString());
-                System.out.println(this.getClass().getSimpleName() + ": xp " + xp.toString());
-                System.out.println(this.getClass().getSimpleName() + ": eta " + eta.toString());
-                System.out.println(this.getClass().getSimpleName() + ": h " + h.toString());
-        }

         double a = track.getBfieldConstant();
         Hep3Vector p0 = track.getP0();
         Hep3Vector x0 = track.getX0();
         double p = p0.magnitude();

-        double rho = a / p0.magnitude();

+        double rho = a / p;

         double A = VecOp.dot(eta,VecOp.cross(p0, h))/p*0.5*rho;
         double B = VecOp.dot(p0,eta)/p;
         double C = VecOp.dot(VecOp.sub(x0,xp),eta);

-        double root1 = (-B + Math.sqrt(B*B-4*A*C)) /(2*A);
-        double root2 = (-B - Math.sqrt(B*B-4*A*C)) /(2*A);
-        double root = -99999999;
-        if(_debug) {

+        double t = B*B-4*A*C;
+        if(t<0) {
+            System.out.println(this.getClass().getSimpleName() + ": getPathLengthToPlaneApprox ERROR t is undefined " + t );

             System.out.println(this.getClass().getSimpleName() + ": p " + p + " rho " + rho + " A " + A + " B " + B + " C " + C);

-        }

+            System.out.println(this.getClass().getSimpleName() + ": track params\n" + track.toString());
+            System.out.println(this.getClass().getSimpleName() + ": xp " + xp.toString());
+            System.out.println(this.getClass().getSimpleName() + ": eta " + eta.toString());
+            System.out.println(this.getClass().getSimpleName() + ": h " + h.toString());
+            System.exit(1);
+        }
+        double root1 = (-B + Math.sqrt(t)) /(2*A);
+        double root2 = (-B - Math.sqrt(t)) /(2*A);
+

         // choose the smallest positive solution
         // if both negative choose the smallest negative ???
         //if(root1==0 || root2==0) root=0;

-        root = Math.abs(root1) <= Math.abs(root2) ? root1 : root2;

+        double root = Math.abs(root1) <= Math.abs(root2) ? root1 : root2;

 //        else if(Math.signum(root1)>0 && Math.signum(root2)<0) root = root1;
 //        else if(Math.signum(root2)>0 && Math.signum(root1)<0) root = root2;
 //        else if(Math.signum(root1)>0 && Math.signum(root2)>0) root =  root1 > root2 ? root2 : root1;

@@ -93,6 +97,12 @@

 //            System.exit(1);
 //        }
         if(_debug) {

+                System.out.println(this.getClass().getSimpleName() + ": getPathLengthToPlaneApprox ");
+                System.out.println(this.getClass().getSimpleName() + ": " + track.toString());
+                System.out.println(this.getClass().getSimpleName() + ": xp " + xp.toString());
+                System.out.println(this.getClass().getSimpleName() + ": eta " + eta.toString());
+                System.out.println(this.getClass().getSimpleName() + ": h " + h.toString());
+                System.out.println(this.getClass().getSimpleName() + ": p " + p + " rho " + rho + " t " + t + " A " + A + " B " + B + " C " + C);

                 System.out.println(this.getClass().getSimpleName() + ": root1 " + root1 + " root2 " + root2 + " -> root " + root);
         }
         return root;