From 6cf7cd87a90a1314332aace1d25b9c0f230dc227 Mon Sep 17 00:00:00 2001
From: Sebastiano Tronto <sebastiano@tronto.net>
Date: Tue, 29 Jul 2025 16:57:21 +0200
Subject: added drslice coordinate

---
 src/solvers/coord/drslice.h | 113 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)
 create mode 100644 src/solvers/coord/drslice.h

(limited to 'src/solvers/coord/drslice.h')

diff --git a/src/solvers/coord/drslice.h b/src/solvers/coord/drslice.h
new file mode 100644
index 0000000..4299b30
--- /dev/null
+++ b/src/solvers/coord/drslice.h
@@ -0,0 +1,113 @@
+/*
+The DRSLICE coordinate is almost identical to DRFINNOE, but it allows for
+the centers of the E layer to be off by a rotation. For this reason we reuse
+much of the code of DRFINNOE. We could make the pruning table 4x smaller
+if we reduced the coordinate by rotations. TODO.
+*/
+
+STATIC cube_t coordinate_drslice_merge(cube_t, cube_t);
+STATIC uint64_t coordinate_drslice_coord(cube_t, const unsigned char *);
+STATIC cube_t coordinate_drslice_cube(uint64_t, const unsigned char *);
+STATIC bool coordinate_drslice_isnasty(uint64_t, const unsigned char *);
+STATIC size_t coordinate_drslice_gendata(unsigned char *);
+STATIC bool is_drslice_solvable(cube_t);
+STATIC bool is_drslice_solved(uint64_t, const unsigned char *);
+
+STATIC coord_t coordinate_drslice = {
+	.name = "DRSLICE",
+	.coord = &coordinate_drslice_coord,
+	.cube = &coordinate_drslice_cube,
+	.isnasty = &coordinate_drslice_isnasty,
+	.gendata = coordinate_drslice_gendata,
+	.max = CLASSES_CP_16 * FACT_8,
+	.trans_mask = TM_UDFIX,
+	.moves_mask_gendata = MM18_DR,
+	.moves_mask_solve = MM18_DR_NOD,
+	.axistrans = {
+		[AXIS_UD] = TRANS_UFr,
+		[AXIS_RL] = TRANS_RFr,
+		[AXIS_FB] = TRANS_FDr,
+	},
+	.is_admissible = &solution_always_valid,
+	.is_solvable = &is_drslice_solvable,
+	.is_solved = &is_drslice_solved,
+	.allow_niss = false,
+	.pruning_distribution = {
+ 		[0] = 3,
+		[1] = 7,
+		[2] = 18,
+		[3] = 111,
+		[4] = 433,
+		[5] = 1618,
+		[6] = 6718,
+		[7] = 29182,
+		[8] = 119873,
+		[9] = 476999,
+		[10] = 1858350,
+		[11] = 6531166,
+		[12] = 18338522,
+		[13] = 32839235,
+		[14] = 34118824,
+		[15] = 17284701
+	},
+	.pruning_max = 15,
+	.sym = {
+		.classes = CLASSES_CP_16,
+		.max = FACT_8,
+		.coord = &coord_cp,
+		.cube = &invcoord_cp,
+		.max2 = FACT_8,
+		.coord2 = &coord_epud,
+		.cube2 = &invcoord_epud,
+		.merge = &coordinate_drslice_merge,
+	},
+};
+
+STATIC cube_t
+coordinate_drslice_merge(cube_t c1, cube_t c2)
+{
+	cube_t merged;
+
+	merged = c1;
+	copy_edges(&merged, c2);
+
+	return merged;
+}
+
+STATIC uint64_t
+coordinate_drslice_coord(cube_t cube, const unsigned char *data)
+{
+	return coord_coord_generic(&coordinate_drslice, cube, data);
+}
+
+STATIC cube_t
+coordinate_drslice_cube(uint64_t i, const unsigned char *data)
+{
+	return coord_cube_generic(&coordinate_drslice, i, data);
+}
+
+STATIC size_t
+coordinate_drslice_gendata(unsigned char *data)
+{
+	return coord_gendata_generic(&coordinate_drslice, data);
+}
+
+STATIC bool
+coordinate_drslice_isnasty(uint64_t i, const unsigned char *data)
+{
+	return coord_isnasty_generic(&coordinate_drslice, i, data);
+}
+
+STATIC bool
+is_drslice_solvable(cube_t cube) {
+	return coord_eo(cube) == 0 &&
+	       coord_eo(transform_edges(cube, TRANS_URr)) == 0 &&
+	       coord_co(cube) == 0;
+}
+
+STATIC bool
+is_drslice_solved(uint64_t i, const unsigned char *data)
+{
+	/* Pre-computed coordinates of U D' (= U' D up to trans) and U2 D2 */
+	return i == 0 || i == 109779816 || i == 68468527;
+}
-- 
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