angle_between now answers in radians

git-svn-id: svn://cook.msm.cam.ac.uk:745/diff-tomo/dtr@94 bf6ca9ba-c028-0410-8290-897cf20841d1

1 files changed, 9 insertions, 2 deletions

diff --git a/src/utils.c b/src/utils.c
index 35f4b88..eaaa036 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -13,6 +13,8 @@
 #include <math.h>
 #include <gsl/gsl_matrix.h>
 
+#include "utils.h"
+
 /* Return the MOST POSITIVE of two numbers */
 unsigned int biggest(signed int a, signed int b) {
 	if ( a>b ) {
@@ -37,13 +39,18 @@ double modulus(double x, double y, double z) {
 	return sqrt(x*x + y*y + z*z);
 }
 
-/* Angle between two vectors.  Answer in degrees */
+/* Angle between two vectors.  Answer in radians */
 double angle_between(double x1, double y1, double z1, double x2, double y2, double z2) {
 
 	double mod1 = modulus(x1, y1, z1);
 	double mod2 = modulus(x2, y2, z2);
-	return ((acos((x1*x2 + y1*y2 + z1*z2) / (mod1*mod2)))/M_PI) * 180;
+	return acos( (x1*x2 + y1*y2 + z1*z2) / (mod1*mod2) );
+
+}
 
+/* As above, answer in degrees */
+double angle_between_d(double x1, double y1, double z1, double x2, double y2, double z2) {
+	return rad2deg(angle_between(x1, y1, z1, x2, y2, z2));
 }
 
 /* Wavelength of an electron (in m) given accelerating potential (in V) */