Added a new pruning table (equivalent to nxopt31). I have not tested it yet, it takes a while to generate.

Plus I have done a whole lot of refactoring in random places because I cannot focus on
one thing at the time.

1 files changed, 141 insertions, 105 deletions

diff --git a/src/steps.c b/src/steps.c
index c4d1279..014b206 100644
--- a/src/steps.c
+++ b/src/steps.c
@@ -36,8 +36,11 @@ static int              estimate_drudfin_drud(DfsArg *arg);
 static int              estimate_htr_drud(DfsArg *arg);
 static int              estimate_htrfin_htr(DfsArg *arg);
 static int              estimate_optimal_HTM(DfsArg *arg);
+static int              estimate_nxopt31_HTM(DfsArg *arg);
 static int              estimate_light_HTM(DfsArg *arg);
 
+static int              estimate_nxoptlike(DfsArg *arg, PruneData *pd);
+
 static bool             always_valid(Alg *alg);
 static bool             validate_singlecw_ending(Alg *alg);
 
@@ -68,7 +71,7 @@ optimal_HTM = {
         .ready     = check_centers,
         .ready_msg = check_centers_msg,
         .is_valid  = always_valid,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = uf,
 
@@ -77,6 +80,25 @@ optimal_HTM = {
 };
 
 Step
+optimal_nxopt31_HTM = {
+        .shortname = "nxopt31",
+        .name      = "Optimal solve (in HTM), nxopt31 table",
+
+        .final     = true,
+        .is_done   = is_solved,
+        .estimate  = estimate_nxopt31_HTM,
+        .ready     = check_centers,
+        .ready_msg = check_centers_msg,
+        .is_valid  = always_valid,
+        .moveset   = &moveset_HTM,
+
+        .pre_trans = uf,
+
+        .tables    = {&pd_nxopt31_HTM, &pd_corners_HTM},
+        .ntables   = 2,
+};
+
+Step
 optimal_light_HTM = {
         .shortname = "light",
         .name      = "Optimal solve (in HTM), small table (500Mb RAM total)",
@@ -87,7 +109,7 @@ optimal_light_HTM = {
         .ready     = check_centers,
         .ready_msg = check_centers_msg,
         .is_valid  = always_valid,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = uf,
 
@@ -107,7 +129,7 @@ eoany_HTM = {
         .ready     = check_centers,
         .ready_msg = check_centers_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = uf,
 
@@ -126,7 +148,7 @@ eofb_HTM = {
         .ready     = check_centers,
         .ready_msg = check_centers_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = uf,
 
@@ -145,7 +167,7 @@ eorl_HTM = {
         .ready     = check_centers,
         .ready_msg = check_centers_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = ur,
 
@@ -164,7 +186,7 @@ eoud_HTM = {
         .ready     = check_centers,
         .ready_msg = check_centers_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = fd,
 
@@ -183,7 +205,7 @@ coany_HTM = {
         .estimate  = estimate_coany_HTM,
         .ready     = NULL,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = uf,
 
@@ -201,7 +223,7 @@ coud_HTM = {
         .estimate  = estimate_coud_HTM,
         .ready     = NULL,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = uf,
 
@@ -219,7 +241,7 @@ corl_HTM = {
         .estimate  = estimate_coud_HTM,
         .ready     = NULL,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = rf,
 
@@ -237,7 +259,7 @@ cofb_HTM = {
         .estimate  = estimate_coud_HTM,
         .ready     = NULL,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = fd,
 
@@ -255,7 +277,7 @@ coany_URF = {
         .estimate  = estimate_coany_URF,
         .ready     = NULL,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_URF,
+        .moveset   = &moveset_URF,
 
         .pre_trans = uf,
 
@@ -273,7 +295,7 @@ coud_URF = {
         .estimate  = estimate_coud_URF,
         .ready     = NULL,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_URF,
+        .moveset   = &moveset_URF,
 
         .pre_trans = uf,
 
@@ -291,7 +313,7 @@ corl_URF = {
         .estimate  = estimate_coud_URF,
         .ready     = NULL,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_URF,
+        .moveset   = &moveset_URF,
 
         .pre_trans = rf,
 
@@ -309,7 +331,7 @@ cofb_URF = {
         .estimate  = estimate_coud_URF,
         .ready     = NULL,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_URF,
+        .moveset   = &moveset_URF,
 
         .pre_trans = fd,
 
@@ -328,7 +350,7 @@ cornershtr_HTM = {
         .estimate  = estimate_cornershtr_HTM,
         .ready     = NULL,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = uf,
 
@@ -346,7 +368,7 @@ cornershtr_URF = {
         .estimate  = estimate_cornershtr_URF,
         .ready     = NULL,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_URF,
+        .moveset   = &moveset_URF,
 
         .pre_trans = uf,
 
@@ -364,7 +386,7 @@ corners_HTM = {
         .estimate  = estimate_corners_HTM,
         .ready     = NULL,
         .is_valid  = always_valid,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = uf,
 
@@ -382,7 +404,7 @@ corners_URF = {
         .estimate  = estimate_corners_URF,
         .ready     = NULL,
         .is_valid  = always_valid,
-        .moveset   = moveset_URF,
+        .moveset   = &moveset_URF,
 
         .pre_trans = uf,
 
@@ -402,7 +424,7 @@ drany_HTM = {
         .ready     = check_centers,
         .ready_msg = check_centers_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = uf,
 
@@ -421,7 +443,7 @@ drud_HTM = {
         .ready     = check_centers,
         .ready_msg = check_centers_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = uf,
 
@@ -440,7 +462,7 @@ drrl_HTM = {
         .ready     = check_centers,
         .ready_msg = check_centers_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = rf,
 
@@ -459,7 +481,7 @@ drfb_HTM = {
         .ready     = check_centers,
         .ready_msg = check_centers_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_HTM,
+        .moveset   = &moveset_HTM,
 
         .pre_trans = fd,
 
@@ -479,7 +501,7 @@ dr_eo = {
         .ready     = check_eofb,
         .ready_msg = check_eo_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_eofb,
+        .moveset   = &moveset_eofb,
 
         .detect    = detect_pretrans_eofb,
 
@@ -498,7 +520,7 @@ dr_eofb = {
         .ready     = check_eofb,
         .ready_msg = check_eo_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_eofb,
+        .moveset   = &moveset_eofb,
 
         .pre_trans = uf,
 
@@ -517,7 +539,7 @@ dr_eorl = {
         .ready     = check_eofb,
         .ready_msg = check_eo_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_eofb,
+        .moveset   = &moveset_eofb,
 
         .pre_trans = ur,
 
@@ -536,7 +558,7 @@ dr_eoud = {
         .ready     = check_eofb,
         .ready_msg = check_eo_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_eofb,
+        .moveset   = &moveset_eofb,
 
         .pre_trans = fd,
 
@@ -555,7 +577,7 @@ drud_eofb = {
         .ready     = check_eofb,
         .ready_msg = check_eo_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_eofb,
+        .moveset   = &moveset_eofb,
 
         .pre_trans = uf,
 
@@ -574,7 +596,7 @@ drrl_eofb = {
         .ready     = check_eofb,
         .ready_msg = check_eo_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_eofb,
+        .moveset   = &moveset_eofb,
 
         .pre_trans = rf,
 
@@ -593,7 +615,7 @@ drud_eorl = {
         .ready     = check_eofb,
         .ready_msg = check_eo_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_eofb,
+        .moveset   = &moveset_eofb,
 
         .pre_trans = ur,
 
@@ -612,7 +634,7 @@ drfb_eorl = {
         .ready     = check_eofb,
         .ready_msg = check_eo_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_eofb,
+        .moveset   = &moveset_eofb,
 
         .pre_trans = fr,
 
@@ -631,7 +653,7 @@ drfb_eoud = {
         .ready     = check_eofb,
         .ready_msg = check_eo_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_eofb,
+        .moveset   = &moveset_eofb,
 
         .pre_trans = fd,
 
@@ -650,7 +672,7 @@ drrl_eoud = {
         .ready     = check_eofb,
         .ready_msg = check_eo_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_eofb,
+        .moveset   = &moveset_eofb,
 
         .pre_trans = rd,
 
@@ -670,7 +692,7 @@ dranyfin_DR = {
         .ready     = check_drud,
         .ready_msg = check_drany_msg,
         .is_valid  = always_valid,
-        .moveset   = moveset_drud,
+        .moveset   = &moveset_drud,
 
         .detect    = detect_pretrans_drud,
 
@@ -689,7 +711,7 @@ drudfin_drud = {
         .ready     = check_drud,
         .ready_msg = check_dr_msg,
         .is_valid  = always_valid,
-        .moveset   = moveset_drud,
+        .moveset   = &moveset_drud,
 
         .pre_trans = uf,
 
@@ -708,7 +730,7 @@ drrlfin_drrl = {
         .ready     = check_drud,
         .ready_msg = check_dr_msg,
         .is_valid  = always_valid,
-        .moveset   = moveset_drud,
+        .moveset   = &moveset_drud,
 
         .pre_trans = rf,
 
@@ -727,7 +749,7 @@ drfbfin_drfb = {
         .ready     = check_drud,
         .ready_msg = check_dr_msg,
         .is_valid  = always_valid,
-        .moveset   = moveset_drud,
+        .moveset   = &moveset_drud,
 
         .pre_trans = fd,
 
@@ -747,7 +769,7 @@ htr_any = {
         .ready     = check_drud,
         .ready_msg = check_drany_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_drud,
+        .moveset   = &moveset_drud,
 
         .detect    = detect_pretrans_drud,
 
@@ -766,7 +788,7 @@ htr_drud = {
         .ready     = check_drud,
         .ready_msg = check_dr_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_drud,
+        .moveset   = &moveset_drud,
 
         .pre_trans = uf,
 
@@ -785,7 +807,7 @@ htr_drrl = {
         .ready     = check_drud,
         .ready_msg = check_dr_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_drud,
+        .moveset   = &moveset_drud,
 
         .pre_trans = rf,
 
@@ -804,7 +826,7 @@ htr_drfb = {
         .ready     = check_drud,
         .ready_msg = check_dr_msg,
         .is_valid  = validate_singlecw_ending,
-        .moveset   = moveset_drud,
+        .moveset   = &moveset_drud,
 
         .pre_trans = fd,
 
@@ -824,7 +846,7 @@ htrfin_htr = {
         .ready     = check_htr,
         .ready_msg = check_htr_msg,
         .is_valid  = always_valid,
-        .moveset   = moveset_htr,
+        .moveset   = &moveset_htr,
 
         .pre_trans = uf,
 
@@ -834,6 +856,7 @@ htrfin_htr = {
 
 Step *steps[NSTEPS] = {
         &optimal_HTM, /* first is default */
+        &optimal_nxopt31_HTM,
         &optimal_light_HTM,
 
         &eoany_HTM,
@@ -1183,6 +1206,19 @@ estimate_htrfin_htr(DfsArg *arg)
 static int
 estimate_optimal_HTM(DfsArg *arg)
 {
+        return estimate_nxoptlike(arg, &pd_khuge_HTM);
+}
+
+static int
+estimate_nxopt31_HTM(DfsArg *arg)
+{
+        return estimate_nxoptlike(arg, &pd_nxopt31_HTM);
+}
+
+/* TODO: also use generic procedure for this */
+static int
+estimate_light_HTM(DfsArg *arg)
+{
         int target, ret;
         Cube aux;
 
@@ -1192,6 +1228,9 @@ estimate_optimal_HTM(DfsArg *arg)
                                        (1<<L) | (1<<L2) | (1<<L3);
         static const uint64_t fbmask = (1<<F) | (1<<F2) | (1<<F3) |
                                        (1<<B) | (1<<B2) | (1<<B3);
+        static const uint64_t htmask = (1<<U2) | (1<<D2) |
+                                       (1<<R2) | (1<<L2) |
+                                       (1<<F2) | (1<<B2);
 
         ret              = -1;
         target           = arg->d - arg->current_alg->len;
@@ -1204,18 +1243,18 @@ estimate_optimal_HTM(DfsArg *arg)
         UPDATECHECKSTOP(ret, arg->ed->corners, target);
 
         /* Normal probing */
-        arg->ed->normal_ud = ptableval(&pd_khuge_HTM, arg->cube);
+        arg->ed->normal_ud = ptableval(&pd_drud_sym16_HTM, arg->cube);
         UPDATECHECKSTOP(ret, arg->ed->normal_ud, target);
         aux = apply_trans(fd, arg->cube);
-        arg->ed->normal_fb = ptableval(&pd_khuge_HTM, aux);
+        arg->ed->normal_fb = ptableval(&pd_drud_sym16_HTM, aux);
         UPDATECHECKSTOP(ret, arg->ed->normal_fb, target);
         aux = apply_trans(rf, arg->cube);
-        arg->ed->normal_rl = ptableval(&pd_khuge_HTM, aux);
+        arg->ed->normal_rl = ptableval(&pd_drud_sym16_HTM, aux);
         UPDATECHECKSTOP(ret, arg->ed->normal_rl, target);
 
         /* If ret == 0, it's solved (corners + triple slice solved) */
         if (ret == 0)
-                return 0;
+                return is_solved(arg->cube) ? 0 : 1;
 
         /* Michel de Bondt's trick*/
         if (arg->ed->normal_ud == arg->ed->normal_fb &&
@@ -1224,21 +1263,30 @@ estimate_optimal_HTM(DfsArg *arg)
         }
 
         /* Inverse probing */
-        aux = arg->inverse = inverse_cube(arg->cube);
-        if (!((1<<arg->last1) & udmask) || (arg->ed->inverse_ud == -1)) {
-                arg->ed->inverse_ud = ptableval(&pd_khuge_HTM, aux);
-        }
-        UPDATECHECKSTOP(ret, arg->ed->inverse_ud, target);
-        if (!((1<<arg->last1) & fbmask) || (arg->ed->inverse_fb == -1)) {
-                aux = apply_trans(fd, arg->inverse);
-                arg->ed->inverse_fb = ptableval(&pd_khuge_HTM, aux);
-        }
-        UPDATECHECKSTOP(ret, arg->ed->inverse_fb, target);
-        if (!((1<<arg->last1) & rlmask) || (arg->ed->inverse_rl == -1)) {
-                aux = apply_trans(rf, arg->inverse);
-                arg->ed->inverse_rl = ptableval(&pd_khuge_HTM, aux);
+        if (!((1<<arg->last1) & htmask)) {
+                aux = arg->inverse = inverse_cube(arg->cube);
+                if (!((1<<arg->last1) & udmask) || (arg->ed->inverse_ud==-1)) {
+                        arg->ed->inverse_ud =
+                            ptableval(&pd_drud_sym16_HTM, aux);
+                }
+                UPDATECHECKSTOP(ret, arg->ed->inverse_ud, target);
+                if (!((1<<arg->last1) & fbmask) || (arg->ed->inverse_fb==-1)) {
+                        aux = apply_trans(fd, arg->inverse);
+                        arg->ed->inverse_fb =
+                            ptableval(&pd_drud_sym16_HTM, aux);
+                }
+                UPDATECHECKSTOP(ret, arg->ed->inverse_fb, target);
+                if (!((1<<arg->last1) & rlmask) || (arg->ed->inverse_rl==-1)) {
+                        aux = apply_trans(rf, arg->inverse);
+                        arg->ed->inverse_rl =
+                            ptableval(&pd_drud_sym16_HTM, aux);
+                }
+                UPDATECHECKSTOP(ret, arg->ed->inverse_rl, target);
+        } else {
+                UPDATECHECKSTOP(ret, arg->ed->inverse_ud, target);
+                UPDATECHECKSTOP(ret, arg->ed->inverse_fb, target);
+                UPDATECHECKSTOP(ret, arg->ed->inverse_rl, target);
         }
-        UPDATECHECKSTOP(ret, arg->ed->inverse_rl, target);
 
         /* Michel de Bondt's trick*/
         if (arg->ed->inverse_ud == arg->ed->inverse_fb &&
@@ -1246,26 +1294,26 @@ estimate_optimal_HTM(DfsArg *arg)
                 UPDATECHECKSTOP(ret, arg->ed->inverse_ud + 1, target);
         }
 
-        /* nxopt trick */
+        /* nxopt trick + half turn trick */
         if (arg->ed->normal_ud == target)
-                arg->badmovesinv |= udmask;
+                arg->badmovesinv |= udmask | htmask;
         if (arg->ed->normal_fb == target)
-                arg->badmovesinv |= fbmask;
+                arg->badmovesinv |= fbmask | htmask;
         if (arg->ed->normal_rl == target)
-                arg->badmovesinv |= rlmask;
+                arg->badmovesinv |= rlmask | htmask;
 
         if (arg->ed->inverse_ud == target)
-                arg->badmoves |= udmask;
+                arg->badmoves |= udmask | htmask;
         if (arg->ed->inverse_fb == target)
-                arg->badmoves |= fbmask;
+                arg->badmoves |= fbmask | htmask;
         if (arg->ed->inverse_rl == target)
-                arg->badmoves |= rlmask;
+                arg->badmoves |= rlmask | htmask;
 
         return arg->ed->oldret = ret;
 }
 
 static int
-estimate_light_HTM(DfsArg *arg)
+estimate_nxoptlike(DfsArg *arg, PruneData *pd)
 {
         int target, ret;
         Cube aux;
@@ -1276,9 +1324,6 @@ estimate_light_HTM(DfsArg *arg)
                                        (1<<L) | (1<<L2) | (1<<L3);
         static const uint64_t fbmask = (1<<F) | (1<<F2) | (1<<F3) |
                                        (1<<B) | (1<<B2) | (1<<B3);
-        static const uint64_t htmask = (1<<U2) | (1<<D2) |
-                                       (1<<R2) | (1<<L2) |
-                                       (1<<F2) | (1<<B2);
 
         ret              = -1;
         target           = arg->d - arg->current_alg->len;
@@ -1291,18 +1336,17 @@ estimate_light_HTM(DfsArg *arg)
         UPDATECHECKSTOP(ret, arg->ed->corners, target);
 
         /* Normal probing */
-        arg->ed->normal_ud = ptableval(&pd_drud_sym16_HTM, arg->cube);
+        arg->ed->normal_ud = ptableval(pd, arg->cube);
         UPDATECHECKSTOP(ret, arg->ed->normal_ud, target);
         aux = apply_trans(fd, arg->cube);
-        arg->ed->normal_fb = ptableval(&pd_drud_sym16_HTM, aux);
+        arg->ed->normal_fb = ptableval(pd, aux);
         UPDATECHECKSTOP(ret, arg->ed->normal_fb, target);
         aux = apply_trans(rf, arg->cube);
-        arg->ed->normal_rl = ptableval(&pd_drud_sym16_HTM, aux);
+        arg->ed->normal_rl = ptableval(pd, aux);
         UPDATECHECKSTOP(ret, arg->ed->normal_rl, target);
 
-        /* If ret == 0, it's solved (corners + triple slice solved) */
         if (ret == 0)
-                return 0;
+                return arg->step->is_done(arg->cube) ? 0 : 1;
 
         /* Michel de Bondt's trick*/
         if (arg->ed->normal_ud == arg->ed->normal_fb &&
@@ -1311,30 +1355,21 @@ estimate_light_HTM(DfsArg *arg)
         }
 
         /* Inverse probing */
-        if (!((1<<arg->last1) & htmask)) {
-                aux = arg->inverse = inverse_cube(arg->cube);
-                if (!((1<<arg->last1) & udmask) || (arg->ed->inverse_ud==-1)) {
-                        arg->ed->inverse_ud =
-                            ptableval(&pd_drud_sym16_HTM, aux);
-                }
-                UPDATECHECKSTOP(ret, arg->ed->inverse_ud, target);
-                if (!((1<<arg->last1) & fbmask) || (arg->ed->inverse_fb==-1)) {
-                        aux = apply_trans(fd, arg->inverse);
-                        arg->ed->inverse_fb =
-                            ptableval(&pd_drud_sym16_HTM, aux);
-                }
-                UPDATECHECKSTOP(ret, arg->ed->inverse_fb, target);
-                if (!((1<<arg->last1) & rlmask) || (arg->ed->inverse_rl==-1)) {
-                        aux = apply_trans(rf, arg->inverse);
-                        arg->ed->inverse_rl =
-                            ptableval(&pd_drud_sym16_HTM, aux);
-                }
-                UPDATECHECKSTOP(ret, arg->ed->inverse_rl, target);
-        } else {
-                UPDATECHECKSTOP(ret, arg->ed->inverse_ud, target);
-                UPDATECHECKSTOP(ret, arg->ed->inverse_fb, target);
-                UPDATECHECKSTOP(ret, arg->ed->inverse_rl, target);
+        aux = arg->inverse = inverse_cube(arg->cube);
+        if (!((1<<arg->last1) & udmask) || (arg->ed->inverse_ud == -1)) {
+                arg->ed->inverse_ud = ptableval(pd, aux);
+        }
+        UPDATECHECKSTOP(ret, arg->ed->inverse_ud, target);
+        if (!((1<<arg->last1) & fbmask) || (arg->ed->inverse_fb == -1)) {
+                aux = apply_trans(fd, arg->inverse);
+                arg->ed->inverse_fb = ptableval(pd, aux);
+        }
+        UPDATECHECKSTOP(ret, arg->ed->inverse_fb, target);
+        if (!((1<<arg->last1) & rlmask) || (arg->ed->inverse_rl == -1)) {
+                aux = apply_trans(rf, arg->inverse);
+                arg->ed->inverse_rl = ptableval(pd, aux);
         }
+        UPDATECHECKSTOP(ret, arg->ed->inverse_rl, target);
 
         /* Michel de Bondt's trick*/
         if (arg->ed->inverse_ud == arg->ed->inverse_fb &&
@@ -1342,24 +1377,25 @@ estimate_light_HTM(DfsArg *arg)
                 UPDATECHECKSTOP(ret, arg->ed->inverse_ud + 1, target);
         }
 
-        /* nxopt trick + half turn trick */
+        /* nxopt trick */
         if (arg->ed->normal_ud == target)
-                arg->badmovesinv |= udmask | htmask;
+                arg->badmovesinv |= udmask;
         if (arg->ed->normal_fb == target)
-                arg->badmovesinv |= fbmask | htmask;
+                arg->badmovesinv |= fbmask;
         if (arg->ed->normal_rl == target)
-                arg->badmovesinv |= rlmask | htmask;
+                arg->badmovesinv |= rlmask;
 
         if (arg->ed->inverse_ud == target)
-                arg->badmoves |= udmask | htmask;
+                arg->badmoves |= udmask;
         if (arg->ed->inverse_fb == target)
-                arg->badmoves |= fbmask | htmask;
+                arg->badmoves |= fbmask;
         if (arg->ed->inverse_rl == target)
-                arg->badmoves |= rlmask | htmask;
+                arg->badmoves |= rlmask;
 
         return arg->ed->oldret = ret;
 }
 
+
 static bool
 always_valid(Alg *alg)
 {