Arithmetic fixes

git-svn-id: svn://cook.msm.cam.ac.uk:745/diff-tomo/dtr@188 bf6ca9ba-c028-0410-8290-897cf20841d1

1 files changed, 12 insertions, 6 deletions

diff --git a/src/refine.c b/src/refine.c
index 01c4bcb..14eba42 100644
--- a/src/refine.c
+++ b/src/refine.c
@@ -146,21 +146,21 @@ static void refine_fit_image(Basis *cell, ImageRecord *image, ReflectionList *ce
 		}
 		
 		if ( shared & INDEX_A ) {
-			double w = h / (h+k+l);
+			double w = abs(h) / (abs(h)+abs(k)+abs(l));
 			cd.a.x += w*dx / h;
 			cd.a.y += w*dy / h;
 			cd.a.z += w*dz / h;
 			n_a++;
 		}
 		if ( shared & INDEX_B ) {
-			double w = k / (h+k+l);
+			double w = abs(k) / (abs(h)+abs(k)+abs(l));
 			cd.b.x += w*dx / k;
 			cd.b.y += w*dy / k;
 			cd.b.z += w*dz / k;
 			n_b++;
 		}
 		if ( shared & INDEX_C ) {
-			double w = l / (h+k+l);
+			double w = abs(l) / (abs(h)+abs(k)+abs(l));
 			cd.c.x += w*dx / l;
 			cd.c.y += w*dy / l;
 			cd.c.z += w*dz / l;
@@ -171,9 +171,15 @@ static void refine_fit_image(Basis *cell, ImageRecord *image, ReflectionList *ce
 	
 	image_feature_list_free(rflist);
 	
-	cd.a.x /= n_a;	cd.a.y /= n_a;	cd.a.z /= n_a;
-	cd.b.x /= n_b;	cd.b.y /= n_b;	cd.b.z /= n_b;
-	cd.c.x /= n_c;	cd.c.y /= n_c;	cd.c.z /= n_c;
+	if ( n_a ) {
+		cd.a.x /= n_a;	cd.a.y /= n_a;	cd.a.z /= n_a;
+	}
+	if ( n_b ) {
+		cd.b.x /= n_b;	cd.b.y /= n_b;	cd.b.z /= n_b;
+	}
+	if ( n_c ) {
+		cd.c.x /= n_c;	cd.c.y /= n_c;	cd.c.z /= n_c;
+	}
 	
 	printf("Total distortion(a) = %+8e %+8e %+8e\n", cd.a.x, cd.a.y, cd.a.z);
 	printf("Total distortion(b) = %+8e %+8e %+8e\n", cd.b.x, cd.b.y, cd.b.z);