1 files changed, 38 insertions, 3 deletions

diff --git a/src/coord.c b/src/coord.c
index 059a7a2..3d5e785 100644
--- a/src/coord.c
+++ b/src/coord.c
@@ -327,9 +327,27 @@ antindex_htr_drud(uint64_t ind)
         /* The returned cube is NOT consistent: corl and cofb can be wrong */
         /* (see cphtr) and eposm can be wrong too (not epose because dr).  */
         Cube ret = {0};
+        static bool initialized = false;
+        static int aux[BINOM8ON4], ep[12], ep2[12];
+        static int eps_solved[4] = {UL, UR, DL, DR};
+        unsigned int i, j, k;
+
+        if (!initialized) {
+                for (i = 0; i < BINOM8ON4; i++) {
+                        for (j = 0; j < 12; j++)
+                                ep[j] = ep2[j] = 0;
+                        index_to_subset(i, 8, 4, ep);
+                        for (j = 0, k = 0; j < 8; j++)
+                                ep2[j] = ep[j/2+4*(j%2)] ? eps_solved[k++] : 0;
+                        aux[i] = array_ep_to_epos(ep2, eps_solved);
+                }
+
+                initialized = true;
+        }
 
         ret       = antindex_cphtr(ind / BINOM8ON4);
-        ret.eposs = (ind % BINOM8ON4) * FACTORIAL4;
+        ret.epose = 0;
+        ret.eposs = aux[ind % BINOM8ON4];
 
         return ret;
 }
@@ -437,8 +455,25 @@ index_drud_eofb(Cube cube)
 static uint64_t
 index_htr_drud(Cube cube)
 {
-        return index_cphtr(cube) * BINOM8ON4 +
-               (cube.eposs / FACTORIAL4) % BINOM8ON4;
+        static bool initialized = false;
+        static int aux[BINOM12ON4], ep[12], ep2[12];
+        static int eps_solved[4] = {UL, UR, DL, DR};
+        unsigned int i, j;
+
+        if (!initialized) {
+                for (i = 0; i < BINOM12ON4; i++) {
+                        for (j = 0; j < 12; j++)
+                                ep[j] = ep2[j] = 0;
+                        epos_to_partial_ep(i*24, ep, eps_solved);
+                        for (j = 0; j < 8; j++)
+                                ep2[j/2 + 4*(j%2)] = ep[j] ? 1 : 0;
+                        aux[i] = subset_to_index(ep2, 8, 4);
+                }
+
+                initialized = true;
+        }
+
+        return index_cphtr(cube) * BINOM8ON4 + aux[cube.eposs/24];
 }
 
 static uint64_t