Improve numerical stability of reprojection

git-svn-id: svn://cook.msm.cam.ac.uk:745/diff-tomo/dtr@285 bf6ca9ba-c028-0410-8290-897cf20841d1

1 files changed, 5 insertions, 0 deletions

diff --git a/src/utils.c b/src/utils.c
index 3fe2e23..30a6e34 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -112,4 +112,9 @@ void matrix_vector_show(const gsl_matrix *m, const gsl_vector *v, const char *pr
 
 }
 
+int sign(double a) {
+	if ( a < 0 ) return -1;
+	if ( a > 0 ) return +1;
+	return 0;
+}