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authorThomas White <taw@physics.org>2010-10-13 10:26:01 +0200
committerThomas White <taw@physics.org>2012-02-22 15:27:03 +0100
commit8c35be50e8380709afe5f84e003f86c3e31ba578 (patch)
tree39cea74f03d12360f81142e8b5b3e8545c7cff62 /src
parentd9b6e615f7d7e2acf5506f82c7dece4a40f3f6cf (diff)
Matched cell must also be right-handed!
Diffstat (limited to 'src')
-rw-r--r--src/cell.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/src/cell.c b/src/cell.c
index 78fc76e1..c07297a5 100644
--- a/src/cell.c
+++ b/src/cell.c
@@ -532,6 +532,24 @@ static int within_tolerance(double a, double b, double percent)
}
+static int right_handed(struct rvec a, struct rvec b, struct rvec c)
+{
+ struct rvec aCb;
+ double aCb_dot_c;
+
+ /* "a" cross "b" */
+ aCb.u = a.v*b.w - a.w*b.v;
+ aCb.v = - (a.u*b.w - a.w*b.u);
+ aCb.w = a.u*b.v - a.v*b.u;
+
+ /* "a cross b" dot "c" */
+ aCb_dot_c = aCb.u*c.u + aCb.v*c.v + aCb.w*c.w;
+
+ if ( aCb_dot_c > 0.0 ) return 1;
+ return 0;
+}
+
+
struct cvec {
struct rvec vec;
float na;
@@ -707,6 +725,10 @@ UnitCell *match_cell(UnitCell *cell, UnitCell *template, int verbose)
/* ... it should be angle 0 ... */
if ( fabs(ang - angles[0]) > angtol ) continue;
+ /* Unit cell must be right-handed */
+ if ( !right_handed(cand[0][i].vec, cand[1][j].vec,
+ cand[2][k].vec) ) continue;
+
fom3 = fom2 + fabs(ang - angles[0]);
fom3 += LWEIGHT * (cand[0][i].fom + cand[1][j].fom
+ cand[2][k].fom);