lcsim/test/org/lcsim/math/coordinatetransform

diff -N CovarianceMatrixTransformerTest.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ CovarianceMatrixTransformerTest.java	31 Mar 2006 01:09:11 -0000	1.1
@@ -0,0 +1,113 @@

+/*
+ * CovarianceMatrixTransformerTest.java
+ *
+ * Created on March 30, 2006, 3:57 PM
+ *
+ * $Id: CovarianceMatrixTransformerTest.java,v 1.1 2006/03/31 01:09:11 ngraf Exp $
+ */
+
+package org.lcsim.math.coordinatetransform;
+
+import junit.framework.TestCase;
+import static java.lang.Math.atan2;
+import static java.lang.Math.sqrt;
+import static java.lang.Math.PI;
+import static java.lang.Math.cos;
+import static java.lang.Math.sin;
+/**
+ *
+ * @author Norman Graf
+ */
+public class CovarianceMatrixTransformerTest extends TestCase
+{
+    
+    /** Creates a new instance of CovarianceMatrixTransformerTest */
+    public  void testCovarianceMatrixTransformer()
+    {
+        double eps = 1E-8;
+        double x = 1.0;
+        double y = 0.0;
+        double sx = .1;
+        double sy = 0.;
+        double sxy = 0.;
+        
+        double[] cov = CovarianceMatrixTransformer.xy2rphi(x, y, sx*sx, sy*sy, sxy);
+//        System.out.println("srr= "+cov[0]);
+//        System.out.println("sphiphi= "+cov[1]);
+//        System.out.println("srphi= "+cov[2]);
+        
+        assertEquals(cov[0], sx*sx, eps);
+        assertEquals(cov[1], sy*sy, eps);
+        assertEquals(cov[2], sxy, eps);
+        
+//        System.out.println(" ");
+        sx = 0.;
+        sy = .1;
+        cov = CovarianceMatrixTransformer.xy2rphi(x, y, sx*sx, sy*sy, sxy);
+//        System.out.println("srr= "+cov[0]);
+//        System.out.println("sphiphi= "+cov[1]);
+//        System.out.println("srphi= "+cov[2]);
+        
+        assertEquals(cov[0], sx*sx, eps);
+        assertEquals(cov[1], sy*sy, eps);
+        assertEquals(cov[2], sxy, eps);
+        
+//        System.out.println(" ");
+        x = .5;
+        y = .5;
+        sx = .1;
+        sy = .1;
+        sxy = -.1;
+        cov = CovarianceMatrixTransformer.xy2rphi(x, y, sx*sx, sy*sy, sxy);
+//        System.out.println("srr= "+cov[0]);
+//        System.out.println("sphiphi= "+cov[1]);
+//        System.out.println("srphi= "+cov[2]);
+        
+        // now let's round-trip...
+        double srr = cov[0];
+        double sphiphi = cov[1];
+        double srphi = cov[2];
+        double r = sqrt(x*x+y*y);
+        double phi = atan2(y,x);
+        
+        
+        cov = CovarianceMatrixTransformer.rphi2xy(r, phi, srr, sphiphi, srphi);
+//        for(int i=0; i<3; ++i) System.out.println("cov["+i+"]= "+cov[i]);
+        
+        
+        assertEquals(sqrt(cov[0]), sx, eps);
+        assertEquals(sqrt(cov[1]), sy, eps);
+        assertEquals(cov[2], sxy, eps);
+        
+        
+//        System.out.println(" ");
+        // start from rPhi...
+        r = 1.;
+        double dr = 0.;
+        phi= PI/4.;
+        double dPhi = .1;
+        srr = dr*dr;
+        sphiphi = dPhi*dPhi;
+        srphi = 0.;
+        
+        cov = CovarianceMatrixTransformer.rphi2xy(r, phi, srr, sphiphi, srphi);
+//        for(int i=0; i<3; ++i) System.out.println("cov["+i+"]= "+cov[i]);
+        
+        
+        // dx should equal dy
+        assertEquals(cov[0], cov[1], eps);
+        // cov term should be neg
+        assertTrue(cov[2]<0);
+        // normalized cov term should be -1
+        assertEquals(cov[2]/cov[0], -1, eps);
+        
+        // now round-trip...
+        x = r*cos(phi);
+        y = r*sin(phi);
+        cov = CovarianceMatrixTransformer.xy2rphi(x, y, cov[0], cov[1], cov[2]);
+//        for(int i=0; i<3; ++i) System.out.println("cov["+i+"]= "+cov[i]);
+        assertEquals(cov[0], srr, eps);
+        assertEquals(cov[1],sphiphi, eps);
+        assertEquals(cov[2], srphi, eps);
+    }
+}