1 files changed, 1 insertions, 0 deletions
diff --git a/src/sfac.c b/src/sfac.c
index 37b57ace..b0b02b45 100644
--- a/src/sfac.c
+++ b/src/sfac.c
@@ -456,6 +456,7 @@ double complex *get_reflections(struct molecule *mol, double en)
 		int i;
 		double s;
 
+		/* We need sin(theta)/lambda = 1/2d */
 		s = resolution(mol->cell, h, k, l);
 
 		/* Atoms are grouped by species for faster calculation */