nissy-classic

commit 40c1aedcd2c8b770ea07ebf7fc22e83ec4b30cb3
parent d2e83077e9bbfcb7f8b4f9506d81cc98397f2e0a
Author: Sebastiano Tronto <sebastiano.tronto@gmail.com>
Date:   Fri,  3 Dec 2021 13:41:24 +0100

Some attempts at using the inverse scramble to get more info for pruning (optimal solving)

Diffstat:
A
nissy
 | 
0

M
src/cube.c
 | 
14
+++++++++-----
M
src/steps.c
 | 
33
+++++++++++++++++++++++----------

3 files changed, 32 insertions(+), 15 deletions(-)
diff --git a/nissy b/nissy
Binary files differ.
diff --git a/src/cube.c b/src/cube.c
@@ -5,7 +5,7 @@
 int
 array_ep_to_epos(int *ep, int *ss)
 {
-	int epos[12] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+	int epos[12] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
 	int eps[4];
 	int i, j, is;
 
@@ -287,11 +287,15 @@ equal(Cube c1, Cube c2)
 Cube
 inverse_cube(Cube cube)
 {
-	CubeArray *arr = new_cubearray(cube, pf_all);
-	CubeArray *inv = new_cubearray((Cube){0}, pf_all);
+	CubeArray *arr, *inv;
 	Cube ret;
 	int i;
 
+	arr = new_cubearray((Cube){0}, pf_all);
+	inv = new_cubearray((Cube){0}, pf_all);
+
+	cube_to_arrays(cube, arr, pf_all);
+
 	for (i = 0; i < 12; i++) {
 		inv->ep[arr->ep[i]]   = i;
 		inv->eofb[arr->ep[i]] = arr->eofb[i];
@@ -317,8 +321,8 @@ inverse_cube(Cube cube)
 }
 
 bool
-is_admissible(Cube cube)
-{
+is_admissible(Cube cube) {
+
 	/* TODO: this should check consistency of different orientations */
 	/* check also that centers are opposite and admissible */
 
diff --git a/src/steps.c b/src/steps.c
@@ -979,29 +979,42 @@ static int
 estimate_optimal_HTM(CubeTarget ct)
 {
 	int dr1, dr2, dr3, cor, ret;
-	Cube cube = ct.cube;
+	Cube inv;
 
-	dr1 = ptableval(&pd_khuge_HTM, cube);
+	dr1 = ptableval(&pd_khuge_HTM, ct.cube);
 	cor = estimate_corners_HTM(ct);
 	ret = MAX(dr1, cor);
-
 	if (ret > ct.target)
 		return ret;
 
-	cube = apply_trans(rf, ct.cube);
-	dr2 = ptableval(&pd_khuge_HTM, cube);
+	dr2 = ptableval(&pd_khuge_HTM, apply_trans(rf, ct.cube));
 	ret = MAX(ret, dr2);
-
 	if (ret > ct.target)
 		return ret;
 
-	cube = apply_trans(fd, ct.cube);
-	dr3 = ptableval(&pd_khuge_HTM, cube);
-
-	/* Michiel de Bondt's trick */
+	dr3 = ptableval(&pd_khuge_HTM, apply_trans(fd, ct.cube));
 	if (dr1 == dr2 && dr2 == dr3 && dr1 != 0)
 		dr3++;
+	ret = MAX(ret, dr3);
+	if (ret > ct.target || ret == 0)
+		return ret;
 
+	/* Inverse cube probing */
+
+	inv = inverse_cube(ct.cube);
+	dr1 = ptableval(&pd_khuge_HTM, inv);
+	ret = MAX(ret, dr1);
+	if (ret > ct.target)
+		return ret;
+
+	dr2 = ptableval(&pd_khuge_HTM, apply_trans(rf, inv));
+	ret = MAX(ret, dr2);
+	if (ret > ct.target)
+		return ret;
+	
+	dr3 = ptableval(&pd_khuge_HTM, apply_trans(fd, inv));
+	if (dr1 == dr2 && dr2 == dr3 && dr1 != 0)
+		dr3++;
 	return MAX(ret, dr3);
 }