WebSVN – Games.Chess Giants – Blame – /engine-crafty/evaluate.c

Rev	Author	Line No.	Line
33	pmbaty	1	#include "chess.h"
108	pmbaty	2	#include "evaluate.h"
33	pmbaty	3	#include "data.h"
154	pmbaty	4	/* last modified 08/03/16 */
33	pmbaty	5	/*
		6	*******************************************************************************
		7	* *
		8	* Evaluate() is used to evaluate the chess board. Broadly, it addresses *
		9	* four (4) distinct areas: (1) material score which is simply a summing of *
		10	* piece types multiplied by piece values; (2) pawn scoring which considers *
		11	* placement of pawns and also evaluates passed pawns, particularly in end- *
		12	* game situations; (3) piece scoring which evaluates the placement of each *
		13	* piece as well as things like piece mobility; (4) king safety which *
108	pmbaty	14	* considers the pawn shelter around the king and enemy pieces and how close *
		15	* they are to assist in a king-side attack. *
33	pmbaty	16	* *
		17	*******************************************************************************
		18	*/
		19	int Evaluate(TREE * RESTRICT tree, int ply, int wtm, int alpha, int beta) {
		20	PAWN_HASH_ENTRY *ptable;
		21	PXOR *pxtable;
108	pmbaty	22	int score, side, can_win = 3, phase, lscore, cutoff;
33	pmbaty	23
		24	/*
108	pmbaty	25	*************************************************************
		26	* *
		27	* First thing we do is if -DSKILL was passed in to the *
		28	* compiler, we burn some time to slow the search down, *
		29	* then we fall into the normal evaluation code. *
		30	* *
		31	*************************************************************
33	pmbaty	32	*/
		33	#if defined(SKILL)
		34	if (skill < 100) {
		35	int i, j;
108	pmbaty	36	for (i = 0; i < burnc[skill / 10] && !abort_search; i++)
		37	for (j = 1; j < 10 && !abort_search; j++)
33	pmbaty	38	burner[j - 1] = burner[j - 1] * burner[j];
108	pmbaty	39	if (TimeCheck(tree, 1))
		40	abort_search = 1;
33	pmbaty	41	}
		42	#endif
		43	/*
108	pmbaty	44	*************************************************************
		45	* *
		46	* First lazy cutoff attempt. If the material score is way *
		47	* below alpha or way above beta (way above means so far *
		48	* above it is very unlikely the positional score can bring *
		49	* the total score back into the alpha / beta window) then *
		50	* we take what is known as a "lazy evaluation exit" and *
		51	* avoid the computational cost of a full evaluation in a *
		52	* position where one side is way ahead or behind. *
		53	* *
		54	*************************************************************
33	pmbaty	55	*/
108	pmbaty	56	cutoff = (TotalPieces(white, occupied) && TotalPieces(black, occupied))
		57	? KNIGHT_VALUE : ROOK_VALUE;
		58	lscore = MaterialSTM(wtm);
		59	if (lscore + cutoff < alpha)
		60	return alpha;
		61	if (lscore - cutoff > beta)
		62	return beta;
33	pmbaty	63	/*
108	pmbaty	64	*************************************************************
		65	* *
		66	* Check for draws where one side seems to be ahead, but *
		67	* has no actual winning chances. One simple example is a *
		68	* king, bishop and rook pawn, with the wrong colored *
		69	* bishop and the enemy king too close to the promotion *
		70	* square. *
		71	* *
		72	* The variable "can_win" uses 2 bits. If White can *
		73	* actually win in this position, bit 1 is set. If Black *
		74	* can actually win in this position, bit 0 is set. If *
		75	* both sides can win, both bits are set. This is used *
		76	* later to drag the score closer to a draw score if the *
		77	* side with the better score can't actually win. *
		78	* *
		79	* Note that we only set these bits in minimal material *
		80	* positions (both sides have < 13 points of material *
		81	* total). Otherwise we assume normal scoring should *
		82	* apply. *
		83	* *
		84	*************************************************************
33	pmbaty	85	*/
108	pmbaty	86	tree->evaluations++;
		87	tree->score_mg = 0;
		88	tree->score_eg = 0;
		89	EvaluateMaterial(tree, wtm);
		90	if (TotalPieces(white, occupied) < 13 && TotalPieces(black, occupied) < 13)
		91	for (side = black; side <= white; side++)
		92	if (!EvaluateWinningChances(tree, side, wtm))
		93	can_win ^= (1 << side);
33	pmbaty	94	/*
108	pmbaty	95	*************************************************************
		96	* *
		97	* Determine if this position should be evaluated to force *
		98	* mate (neither side has pawns) or if it should be *
		99	* evaluated normally. *
		100	* *
		101	* Note the special case of no pawns, one side is ahead in *
		102	* total material, but the game is a hopeless draw. KRN vs *
		103	* KR is one example. If EvaluateWinningChances() *
		104	* determines that the side with extra material can not *
		105	* win, the score is pulled closer to a draw although it *
		106	* can not collapse completely to the drawscore as it is *
		107	* possible to lose KRB vs KR if the KR side lets the king *
		108	* get trapped on the edge of the board. *
		109	* *
		110	*************************************************************
33	pmbaty	111	*/
		112	tree->all_pawns = Pawns(black) \| Pawns(white);
		113	if (!tree->all_pawns) {
		114	if (TotalPieces(white, occupied) > 3 \|\| TotalPieces(black, occupied) > 3) {
		115	if (Material > 0)
		116	EvaluateMate(tree, white);
		117	else if (Material < 0)
		118	EvaluateMate(tree, black);
108	pmbaty	119	if (tree->score_eg > DrawScore(1) && !(can_win & 2))
		120	tree->score_eg = tree->score_eg / 16;
		121	if (tree->score_eg < DrawScore(1) && !(can_win & 1))
		122	tree->score_eg = tree->score_eg / 16;
33	pmbaty	123	#if defined(SKILL)
		124	if (skill < 100)
156	pmbaty	125	tree->score_eg = (int) // Pierre-Marie Baty -- added type cast
		126	(skill * tree->score_eg / 100 + ((100 -
33	pmbaty	127	skill) * PAWN_VALUE * (uint64_t) Random32() /
156	pmbaty	128	0x100000000ull) / 100);
33	pmbaty	129	#endif
		130	return (wtm) ? tree->score_eg : -tree->score_eg;
		131	}
		132	}
		133	/*
108	pmbaty	134	*************************************************************
		135	* *
		136	* Now evaluate pawns. If the pawn hash signature has not *
		137	* changed from the last entry to Evaluate() then we *
		138	* already have everything we need in the pawn hash entry. *
		139	* In this case, we do not need to call EvaluatePawns() at *
		140	* all. EvaluatePawns() does all of the analysis for *
		141	* information specifically regarding only pawns. In many *
		142	* cases, it merely records the presence/absence of *
		143	* positional pawn features because those features also *
		144	* depends on pieces. *
		145	* *
		146	* Note that anything put into EvaluatePawns() can only *
		147	* consider the placement of pawns. Kings or other pieces *
		148	* can not influence the score because those pieces are not *
		149	* hashed into the pawn hash signature. Violating this *
		150	* principle leads to lots of very difficult and *
		151	* challenging debugging problems. *
		152	* *
		153	*************************************************************
33	pmbaty	154	*/
		155	else {
		156	if (PawnHashKey == tree->pawn_score.key) {
		157	tree->score_mg += tree->pawn_score.score_mg;
		158	tree->score_eg += tree->pawn_score.score_eg;
		159	}
		160	/*
108	pmbaty	161	*************************************************************
		162	* *
		163	* First check to see if this position has been handled *
		164	* before. If so, we can skip the work saved in the pawn *
		165	* hash table. *
		166	* *
		167	*************************************************************
33	pmbaty	168	*/
		169	else {
		170	ptable = pawn_hash_table + (PawnHashKey & pawn_hash_mask);
		171	pxtable = (PXOR *) & (tree->pawn_score);
		172	tree->pawn_score = *ptable;
108	pmbaty	173	tree->pawn_score.key ^= pxtable->entry[1] ^ pxtable->entry[2];
33	pmbaty	174	if (tree->pawn_score.key != PawnHashKey) {
		175	tree->pawn_score.key = PawnHashKey;
		176	tree->pawn_score.score_mg = 0;
		177	tree->pawn_score.score_eg = 0;
		178	for (side = black; side <= white; side++)
		179	EvaluatePawns(tree, side);
		180	ptable->key =
108	pmbaty	181	pxtable->entry[0] ^ pxtable->entry[1] ^ pxtable->entry[2];
		182	memcpy((char ) ptable + 8, (char ) &(tree->pawn_score) + 8,
		183	sizeof(PAWN_HASH_ENTRY) - 8);
33	pmbaty	184	}
		185	tree->score_mg += tree->pawn_score.score_mg;
		186	tree->score_eg += tree->pawn_score.score_eg;
		187	}
		188	/*
108	pmbaty	189	*************************************************************
		190	* *
		191	* If there are any passed pawns, first call *
		192	* EvaluatePassedPawns() to evaluate them. Then, if one *
		193	* side has a passed pawn and the other side has no pieces, *
		194	* call EvaluatePassedPawnRaces() to see if the passed pawn *
		195	* can be stopped from promoting. *
		196	* *
		197	*************************************************************
33	pmbaty	198	*/
		199	if (tree->pawn_score.passed[black] \|\| tree->pawn_score.passed[white]) {
		200	for (side = black; side <= white; side++)
		201	if (tree->pawn_score.passed[side])
		202	EvaluatePassedPawns(tree, side, wtm);
		203	if ((TotalPieces(white, occupied) == 0 &&
		204	tree->pawn_score.passed[black])
		205	\|\| (TotalPieces(black, occupied) == 0 &&
		206	tree->pawn_score.passed[white]))
		207	EvaluatePassedPawnRaces(tree, wtm);
		208	}
		209	}
		210	/*
108	pmbaty	211	*************************************************************
		212	* *
		213	* Call EvaluateCastling() to evaluate castling potential. *
		214	* Note we only do this when that side has not castled at *
		215	* the root. *
		216	* *
		217	*************************************************************
33	pmbaty	218	*/
		219	for (side = black; side <= white; side++)
108	pmbaty	220	if (Castle(1, side) > 0)
		221	EvaluateCastling(tree, ply, side);
33	pmbaty	222	/*
108	pmbaty	223	*************************************************************
		224	* *
		225	* The "dangerous" flag simply indicates whether that side *
		226	* has enough material to whip up a mating attack if the *
		227	* other side is careless (Q + minor or better, or RR + two *
		228	* minors or better). *
		229	* *
		230	*************************************************************
33	pmbaty	231	*/
108	pmbaty	232	tree->dangerous[white] = (Queens(white) && TotalPieces(white, occupied) > 9)
		233	\|\| (TotalPieces(white, rook) > 1 && TotalPieces(white, occupied) > 15);
		234	tree->dangerous[black] = (Queens(black) && TotalPieces(black, occupied) > 9)
		235	\|\| (TotalPieces(black, rook) > 1 && TotalPieces(black, occupied) > 15);
		236	/*
		237	*************************************************************
		238	* *
		239	* Second lazy evaluation test. We have computed the large *
		240	* positional scores (except for king safety). If the *
		241	* score is too far outside the alpha/beta window, we skip *
		242	* the piece scoring which is the most expensive of all the *
		243	* evaluation terms, and simply use what we have at this *
		244	* point. *
		245	* *
		246	*************************************************************
		247	*/
33	pmbaty	248	phase =
		249	Min(62, TotalPieces(white, occupied) + TotalPieces(black, occupied));
		250	score = ((tree->score_mg * phase) + (tree->score_eg * (62 - phase))) / 62;
		251	lscore = (wtm) ? score : -score;
108	pmbaty	252	int w_mat = (2 * TotalPieces(white, rook)) + TotalPieces(white,
		253	knight) + TotalPieces(white, bishop);
		254	int b_mat = (2 * TotalPieces(black, rook)) + TotalPieces(black,
		255	knight) + TotalPieces(black, bishop);
		256	cutoff = 72 + (w_mat + b_mat) * 8 + abs(w_mat - b_mat) * 16;
		257	if (tree->dangerous[white] \|\| tree->dangerous[black])
		258	cutoff += 35;
		259	/*
		260	*************************************************************
		261	* *
		262	* Then evaluate pieces if the lazy eval test fails. *
		263	* *
		264	* Note: We MUST evaluate kings last, since their scoring *
		265	* depends on the tropism scores computed by the other *
		266	* piece evaluators. Do NOT try to collapse the following *
		267	* loops into one loop. That will break things since it *
		268	* would violate the kings last rule. More importantly *
		269	* there is no benefit as the loops below are unrolled by *
		270	* the compiler anyway. *
		271	* *
		272	*************************************************************
		273	*/
33	pmbaty	274	if (lscore + cutoff > alpha && lscore - cutoff < beta) {
		275	tree->tropism[white] = 0;
		276	tree->tropism[black] = 0;
		277	for (side = black; side <= white; side++)
154	pmbaty	278	if (Knights(side))
		279	EvaluateKnights(tree, side);
33	pmbaty	280	for (side = black; side <= white; side++)
154	pmbaty	281	if (Bishops(side))
		282	EvaluateBishops(tree, side);
33	pmbaty	283	for (side = black; side <= white; side++)
154	pmbaty	284	if (Rooks(side))
		285	EvaluateRooks(tree, side);
33	pmbaty	286	for (side = black; side <= white; side++)
154	pmbaty	287	if (Queens(side))
		288	EvaluateQueens(tree, side);
33	pmbaty	289	for (side = black; side <= white; side++)
108	pmbaty	290	EvaluateKing(tree, ply, side);
33	pmbaty	291	}
		292	/*
108	pmbaty	293	*************************************************************
		294	* *
		295	* Caclulate the final score, which is interpolated between *
		296	* the middlegame score and endgame score based on the *
		297	* material left on the board. *
		298	* *
		299	* Adjust the score if one side can't win, but the score *
		300	* actually favors that side significantly. *
		301	* *
		302	*************************************************************
33	pmbaty	303	*/
		304	score = ((tree->score_mg * phase) + (tree->score_eg * (62 - phase))) / 62;
		305	score = EvaluateDraws(tree, ply, can_win, score);
		306	#if defined(SKILL)
		307	if (skill < 100)
156	pmbaty	308	score = (int) // Pierre-Marie Baty -- added type cast
		309	(skill * score / 100 + ((100 -
33	pmbaty	310	skill) * PAWN_VALUE * (uint64_t) Random32() / 0x100000000ull) /
156	pmbaty	311	100);
33	pmbaty	312	#endif
		313	return (wtm) ? score : -score;
		314	}
		315
108	pmbaty	316	/* last modified 10/19/15 */
33	pmbaty	317	/*
		318	*******************************************************************************
		319	* *
		320	* EvaluateBishops() is used to evaluate bishops. *
		321	* *
		322	*******************************************************************************
		323	*/
		324	void EvaluateBishops(TREE * RESTRICT tree, int side) {
		325	uint64_t temp, moves;
108	pmbaty	326	int square, special, i, mobility;
		327	int score_eg = 0, score_mg = 0, enemy = Flip(side), tpawns;
33	pmbaty	328	/*
		329	************************************************************
		330	* *
		331	* First, locate each bishop and add in its piece/square *
108	pmbaty	332	* table score. *
33	pmbaty	333	* *
		334	************************************************************
		335	*/
		336	for (temp = Bishops(side); temp; temp &= temp - 1) {
		337	square = LSB(temp);
		338	score_mg += bval[mg][side][square];
		339	score_eg += bval[eg][side][square];
		340	/*
		341	************************************************************
		342	* *
		343	* Evaluate for "outposts" which is a bishop that can't be *
		344	* driven off by an enemy pawn, and which is supported by *
		345	* a friendly pawn. *
		346	* *
		347	* If the enemy has NO minor to take this bishop, then *
		348	* increase the bonus. *
		349	* *
		350	************************************************************
		351	*/
108	pmbaty	352	special = bishop_outpost[side][square];
		353	if (special) {
		354	if (!(mask_pattacks[enemy][square] & Pawns(enemy))) {
		355	if (pawn_attacks[enemy][square] & Pawns(side)) {
		356	special += special / 2;
		357	if (!Knights(enemy) && !(Color(square) & Bishops(enemy)))
		358	special += bishop_outpost[side][square];
33	pmbaty	359	}
108	pmbaty	360	score_eg += special;
		361	score_mg += special;
33	pmbaty	362	}
108	pmbaty	363	}
33	pmbaty	364	/*
		365	************************************************************
		366	* *
108	pmbaty	367	* Next we count the number of friendly pawns on the same *
		368	* color squares as the bishop. This is a bad thing since *
		369	* it restricts the bishop's ability to move. We only do *
		370	* this if there is only one bishop for this side. *
33	pmbaty	371	* *
		372	************************************************************
		373	*/
108	pmbaty	374	if (TotalPieces(side, bishop) == 1) {
		375	if (dark_squares & SetMask(square))
		376	tpawns = PopCnt(dark_squares & Pawns(side));
		377	else
		378	tpawns = PopCnt(~dark_squares & Pawns(side));
		379	score_mg -= tpawns * bishop_pawns_on_color[mg];
		380	score_eg -= tpawns * bishop_pawns_on_color[eg];
33	pmbaty	381	}
		382	/*
		383	************************************************************
		384	* *
108	pmbaty	385	* Mobility counts the number of squares the bishop *
		386	* attacks, excluding squares with friendly pieces, and *
		387	* weighs each square according to centralization. *
33	pmbaty	388	* *
		389	************************************************************
		390	*/
		391	mobility = BishopMobility(square, OccupiedSquares);
		392	if (mobility < 0 && (pawn_attacks[enemy][square] & Pawns(side))
		393	&& (File(square) == FILEA \|\| File(square) == FILEH))
		394	mobility -= 8;
		395	score_mg += mobility;
		396	score_eg += mobility;
		397	/*
		398	************************************************************
		399	* *
		400	* Adjust the tropism count for this piece. *
		401	* *
		402	************************************************************
		403	*/
		404	if (tree->dangerous[side]) {
		405	moves = king_attacks[KingSQ(enemy)];
108	pmbaty	406	i = ((bishop_attacks[square] & moves) &&
		407	((BishopAttacks(square, OccupiedSquares & ~Queens(side))) & moves))
		408	? 1 : Distance(square, KingSQ(enemy));
		409	tree->tropism[side] += king_tropism_b[i];
33	pmbaty	410	}
		411	}
108	pmbaty	412	/*
		413	************************************************************
		414	* *
		415	* Add a bonus if this side has a pair of bishops, which *
		416	* can become very strong in open positions. *
		417	* *
		418	************************************************************
		419	*/
		420	if (TotalPieces(side, bishop) > 1) {
		421	score_mg += bishop_pair[mg];
		422	score_eg += bishop_pair[eg];
		423	}
154	pmbaty	424	/*
		425	************************************************************
		426	* *
		427	* Check for pawns on both wings, which makes a bishop *
		428	* even more valuable against an enemy knight *
		429	* *
		430	************************************************************
		431	*/
		432	else {
		433	if (tree->all_pawns & mask_fgh && tree->all_pawns & mask_abc) {
		434	score_mg += bishop_wing_pawns[mg];
		435	score_eg += bishop_wing_pawns[eg];
		436	}
		437	}
33	pmbaty	438	tree->score_mg += sign[side] * score_mg;
		439	tree->score_eg += sign[side] * score_eg;
		440	}
		441
108	pmbaty	442	/* last modified 01/03/15 */
33	pmbaty	443	/*
		444	*******************************************************************************
		445	* *
108	pmbaty	446	* EvaluateCastling() is called when "side" has not castled at the root. *
		447	* Its main purpose is to determine if it has either castled somewhere in *
		448	* the tree, or else has lost all (or some) castling rights, which reduces *
		449	* options significantly. *
33	pmbaty	450	* *
		451	*******************************************************************************
		452	*/
108	pmbaty	453	void EvaluateCastling(TREE * RESTRICT tree, int ply, int side) {
		454	int enemy = Flip(side), oq, score_mg = 0;;
33	pmbaty	455
		456	/*
		457	************************************************************
		458	* *
108	pmbaty	459	* If the king castled during the search, we are done and *
		460	* we leave it to EvaluateKing() to figure out how safe it *
		461	* is. If it has not castled, we give a significant *
		462	* penalty if the king moves since that loses all castling *
		463	* rights, otherwise we give a smaller penalty for moving *
		464	* a rook and giving up castling rights to that side of *
		465	* the board. The penalty is always increased if the *
		466	* opponent has a queen since the position is much more *
		467	* dangerous. *
33	pmbaty	468	* *
		469	************************************************************
		470	*/
108	pmbaty	471	oq = (Queens(enemy)) ? 3 : 1;
		472	if (Castle(ply, side) != Castle(1, side)) {
		473	if (Castle(ply, side) == 0)
		474	score_mg -= oq * development_losing_castle;
		475	else if (Castle(ply, side) > 0)
		476	score_mg -= (oq * development_losing_castle) / 2;
		477	} else
		478	score_mg -= oq * development_not_castled;
33	pmbaty	479	tree->score_mg += sign[side] * score_mg;
		480	}
		481
108	pmbaty	482	/* last modified 01/03/15 */
33	pmbaty	483	/*
		484	*******************************************************************************
		485	* *
		486	* EvaluateDraws() is used to adjust the score based on whether the side *
		487	* that appears to be better according the computed score can actually win *
		488	* the game or not. If the answer is "no" then the score is reduced *
		489	* significantly to reflect the lack of winning chances. *
		490	* *
		491	*******************************************************************************
		492	*/
		493	int EvaluateDraws(TREE * RESTRICT tree, int ply, int can_win, int score) {
		494	/*
		495	************************************************************
		496	* *
		497	* If the ending has only bishops of opposite colors, the *
108	pmbaty	498	* score is pulled closer to a draw. *
33	pmbaty	499	* *
		500	* If this is a pure BOC ending, it is very drawish unless *
		501	* one side has at least 4 pawns. More pawns makes it *
		502	* harder for a bishop and king to stop them all from *
		503	* advancing. *
		504	* *
108	pmbaty	505	* If the following are both true: *
		506	* *
		507	* black and white have less than a queen left (pieces *
		508	* only). *
		509	* *
		510	* both have one bishop and they are opposite colored. *
		511	* *
		512	* then either *
		513	* *
		514	* (a) both have just one bishop, both have less than 4 *
		515	* pawns or one side has only one more pawn than the *
		516	* other side then score is divided by 2 with draw score *
		517	* added in; or *
		518	* *
		519	* (b) pieces are equal, then score is reduced by 25% *
		520	* with draw score added in. *
		521	* *
33	pmbaty	522	************************************************************
		523	*/
		524	if (TotalPieces(white, occupied) <= 8 && TotalPieces(black, occupied) <= 8) {
		525	if (TotalPieces(white, bishop) == 1 && TotalPieces(black, bishop) == 1)
		526	if (square_color[LSB(Bishops(black))] !=
		527	square_color[LSB(Bishops(white))]) {
		528	if (TotalPieces(white, occupied) == 3 &&
		529	TotalPieces(black, occupied) == 3 &&
		530	((TotalPieces(white, pawn) < 4 && TotalPieces(black, pawn) < 4)
		531	\|\| Abs(TotalPieces(white, pawn) - TotalPieces(black,
		532	pawn)) < 2))
		533	score = score / 2 + DrawScore(1);
		534	else if (TotalPieces(white, occupied) == TotalPieces(black, occupied))
		535	score = 3 * score / 4 + DrawScore(1);
		536	}
		537	}
108	pmbaty	538	/*
		539	************************************************************
		540	* *
		541	* Final score adjustment. If the score says white is *
		542	* better, but can_win says white can not win, or if the *
		543	* score says black is better, but can_win says black can *
		544	* not win, then we divide the score by 16, and then add *
		545	* in the draw score. If the can_win says neither side *
		546	* can win, we just set the score to draw score and exit. *
		547	* *
		548	************************************************************
		549	*/
33	pmbaty	550	if (can_win != 3) {
108	pmbaty	551	if (can_win & 1) {
		552	if (score > DrawScore(1))
		553	score = score / 16 + DrawScore(1);
		554	} else if (can_win & 2) {
		555	if (score < DrawScore(1))
		556	score = score / 16 + DrawScore(1);
		557	} else
		558	score = DrawScore(1);
33	pmbaty	559	}
		560	/*
		561	************************************************************
		562	* *
		563	* If we are running into the 50-move rule, then start *
		564	* dragging the score toward draw. This is the idea of a *
		565	* "weariness factor" as mentioned by Dave Slate many *
		566	* times. This avoids slamming into a draw at move 50 and *
		567	* having to move something quickly, rather than slowly *
		568	* discovering that the score is dropping and that pushing *
		569	* a pawn or capturing something will cause it to go back *
		570	* to its correct value a bit more smoothly. *
		571	* *
		572	************************************************************
		573	*/
		574	if (Reversible(ply) > 80) {
108	pmbaty	575	int closeness = 101 - Reversible(ply);
33	pmbaty	576
108	pmbaty	577	score = DrawScore(1) + score * closeness / 20;
33	pmbaty	578	}
		579	return score;
		580	}
		581
108	pmbaty	582	/* last modified 01/03/15 */
33	pmbaty	583	/*
		584	*******************************************************************************
		585	* *
		586	* EvaluateHasOpposition() is used to determine if one king stands in *
		587	* "opposition" to the other. If the kings are opposed on the same file or *
		588	* else are opposed on the same diagonal, then the side not-to-move has the *
		589	* opposition and the side-to-move must give way. *
		590	* *
		591	*******************************************************************************
		592	*/
		593	int EvaluateHasOpposition(int on_move, int king, int enemy_king) {
		594	int file_distance, rank_distance;
		595
		596	file_distance = FileDistance(king, enemy_king);
		597	rank_distance = RankDistance(king, enemy_king);
		598	if (rank_distance < 2)
		599	return 1;
		600	if (on_move) {
		601	if (rank_distance & 1)
		602	rank_distance--;
		603	if (file_distance & 1)
		604	file_distance--;
		605	}
		606	if (!(file_distance & 1) && !(rank_distance & 1))
		607	return 1;
		608	return 0;
		609	}
		610
108	pmbaty	611	/* last modified 01/03/15 */
33	pmbaty	612	/*
		613	*******************************************************************************
		614	* *
108	pmbaty	615	* EvaluateKing() is used to evaluate a king. *
33	pmbaty	616	* *
		617	*******************************************************************************
		618	*/
108	pmbaty	619	void EvaluateKing(TREE * RESTRICT tree, int ply, int side) {
33	pmbaty	620	int score_eg = 0, score_mg = 0, defects;
		621	int ksq = KingSQ(side), enemy = Flip(side);
		622
		623	/*
		624	************************************************************
		625	* *
		626	* First, check for where the king should be if this is an *
108	pmbaty	627	* endgame. The basic idea is to centralize unless the *
		628	* king is needed to deal with a passed enemy pawn. *
33	pmbaty	629	* *
		630	************************************************************
		631	*/
108	pmbaty	632	score_eg += kval[side][ksq];
33	pmbaty	633	/*
		634	************************************************************
		635	* *
		636	* Do castle scoring, if the king has castled, the pawns *
		637	* in front are important. If not castled yet, the pawns *
		638	* on the kingside should be preserved for this. *
		639	* *
		640	************************************************************
		641	*/
		642	if (tree->dangerous[enemy]) {
		643	defects = 0;
		644	if (Castle(ply, side) <= 0) {
108	pmbaty	645	if (File(ksq) > FILEE)
		646	defects = tree->pawn_score.defects_k[side];
		647	else if (File(ksq) < FILED)
		648	defects = tree->pawn_score.defects_q[side];
		649	else
		650	defects = tree->pawn_score.defects_m[side];
33	pmbaty	651	} else {
		652	if (Castle(ply, side) == 3)
		653	defects =
		654	Min(Min(tree->pawn_score.defects_k[side],
108	pmbaty	655	tree->pawn_score.defects_m[side]),
33	pmbaty	656	tree->pawn_score.defects_q[side]);
		657	else if (Castle(ply, side) == 1)
		658	defects =
		659	Min(tree->pawn_score.defects_k[side],
108	pmbaty	660	tree->pawn_score.defects_m[side]);
33	pmbaty	661	else
		662	defects =
		663	Min(tree->pawn_score.defects_q[side],
108	pmbaty	664	tree->pawn_score.defects_m[side]);
33	pmbaty	665	if (defects < 3)
		666	defects = 3;
		667	}
		668	/*
		669	************************************************************
		670	* *
		671	* Fold in the king tropism and king pawn shelter scores *
		672	* together. *
		673	* *
		674	************************************************************
		675	*/
		676	if (tree->tropism[enemy] < 0)
		677	tree->tropism[enemy] = 0;
		678	else if (tree->tropism[enemy] > 15)
		679	tree->tropism[enemy] = 15;
		680	if (defects > 15)
		681	defects = 15;
		682	score_mg -= king_safety[defects][tree->tropism[enemy]];
		683	}
		684	tree->score_mg += sign[side] * score_mg;
		685	tree->score_eg += sign[side] * score_eg;
		686	}
		687
108	pmbaty	688	/* last modified 01/03/15 */
33	pmbaty	689	/*
		690	*******************************************************************************
		691	* *
		692	* EvaluateKingsFile computes defects for a file, based on whether the file *
		693	* is open or half-open. If there are friendly pawns still on the file, *
		694	* they are penalized for advancing in front of the king. *
		695	* *
		696	*******************************************************************************
		697	*/
108	pmbaty	698	int EvaluateKingsFile(TREE * RESTRICT tree, int side, int first, int last) {
		699	int defects = 0, file, enemy = Flip(side);
33	pmbaty	700
108	pmbaty	701	for (file = first; file <= last; file++)
33	pmbaty	702	if (!(file_mask[file] & tree->all_pawns))
		703	defects += open_file[file];
		704	else {
		705	if (!(file_mask[file] & Pawns(enemy)))
		706	defects += half_open_file[file] / 2;
		707	else
		708	defects +=
108	pmbaty	709	pawn_defects[side][Rank(MostAdvanced(enemy,
33	pmbaty	710	file_mask[file] & Pawns(enemy)))];
		711	if (!(file_mask[file] & Pawns(side)))
		712	defects += half_open_file[file];
		713	else if (!(Pawns(side) & SetMask(sqflip[side][A2] + file))) {
		714	defects++;
		715	if (!(Pawns(side) & SetMask(sqflip[side][A3] + file)))
		716	defects++;
		717	}
		718	}
		719	return defects;
		720	}
		721
108	pmbaty	722	/* last modified 10/19/15 */
33	pmbaty	723	/*
		724	*******************************************************************************
		725	* *
		726	* EvaluateKnights() is used to evaluate knights. *
		727	* *
		728	*******************************************************************************
		729	*/
		730	void EvaluateKnights(TREE * RESTRICT tree, int side) {
		731	uint64_t temp;
108	pmbaty	732	int square, special, i, score_eg = 0, score_mg = 0, enemy = Flip(side);
33	pmbaty	733
		734	/*
		735	************************************************************
		736	* *
		737	* First fold in centralization score from the piece/ *
		738	* square table "nval". *
		739	* *
		740	************************************************************
		741	*/
		742	for (temp = Knights(side); temp; temp &= temp - 1) {
		743	square = LSB(temp);
		744	score_mg += nval[mg][side][square];
		745	score_eg += nval[eg][side][square];
		746	/*
		747	************************************************************
		748	* *
		749	* Evaluate for "outposts" which is a knight that can't *
		750	* be driven off by an enemy pawn, and which is supported *
		751	* by a friendly pawn. *
		752	* *
		753	* If the enemy has NO minor to take this knight, then *
		754	* increase the bonus. *
		755	* *
		756	************************************************************
		757	*/
108	pmbaty	758	special = knight_outpost[side][square];
		759	if (special && !(mask_pattacks[enemy][square] & Pawns(enemy))) {
33	pmbaty	760	if (pawn_attacks[enemy][square] & Pawns(side)) {
108	pmbaty	761	special += special / 2;
33	pmbaty	762	if (!Knights(enemy) && !(Color(square) & Bishops(enemy)))
108	pmbaty	763	special += knight_outpost[side][square];
33	pmbaty	764	}
108	pmbaty	765	score_eg += special;
		766	score_mg += special;
33	pmbaty	767	}
		768	/*
		769	************************************************************
		770	* *
		771	* Adjust the tropism count for this piece. *
		772	* *
		773	************************************************************
		774	*/
		775	if (tree->dangerous[side]) {
108	pmbaty	776	i = Distance(square, KingSQ(enemy));
		777	tree->tropism[side] += king_tropism_n[i];
33	pmbaty	778	}
		779	}
		780	tree->score_mg += sign[side] * score_mg;
		781	tree->score_eg += sign[side] * score_eg;
		782	}
		783
108	pmbaty	784	/* last modified 03/30/15 */
33	pmbaty	785	/*
		786	*******************************************************************************
		787	* *
		788	* EvaluateMate() is used to evaluate positions where neither side has pawns *
		789	* and one side has enough material to force checkmate. It simply trys to *
		790	* force the losing king to the edge of the board, and then to the corner *
		791	* where mates are easier to find. *
		792	* *
		793	*******************************************************************************
		794	*/
		795	void EvaluateMate(TREE * RESTRICT tree, int side) {
108	pmbaty	796	int mate_score = 0, enemy = Flip(side);
33	pmbaty	797
		798	/*
		799	************************************************************
		800	* *
108	pmbaty	801	* If the winning side has a bishop + knight and the other *
		802	* side has no pieces or pawns, then use the special *
		803	* bishop_knight scoring board for the losing king to *
		804	* force it to the right corner for mate. *
33	pmbaty	805	* *
		806	************************************************************
		807	*/
108	pmbaty	808	if (!TotalPieces(enemy, occupied) && TotalPieces(side, bishop) == 1 &&
		809	TotalPieces(side, knight) == 1) {
33	pmbaty	810	if (dark_squares & Bishops(side))
		811	mate_score = b_n_mate_dark_squares[KingSQ(enemy)];
		812	else
		813	mate_score = b_n_mate_light_squares[KingSQ(enemy)];
		814	}
		815	/*
		816	************************************************************
		817	* *
108	pmbaty	818	* The winning side has to force the losing king to the *
33	pmbaty	819	* edge of the board. *
		820	* *
		821	************************************************************
		822	*/
108	pmbaty	823	else
33	pmbaty	824	mate_score = mate[KingSQ(enemy)];
108	pmbaty	825	/*
		826	************************************************************
		827	* *
		828	* And for either, it is important to bring the winning *
		829	* king to help force mate. *
		830	* *
		831	************************************************************
		832	*/
		833	mate_score -= Distance(KingSQ(side), KingSQ(enemy)) * king_king_tropism;
33	pmbaty	834	tree->score_eg += sign[side] * mate_score;
		835	}
		836
108	pmbaty	837	/* last modified 10/19/15 */
33	pmbaty	838	/*
		839	*******************************************************************************
		840	* *
		841	* EvaluateMaterial() is used to evaluate material on the board. It really *
		842	* accomplishes detecting cases where one side has made a 'bad trade' as the *
		843	* comments below show. *
		844	* *
		845	*******************************************************************************
		846	*/
		847	void EvaluateMaterial(TREE * RESTRICT tree, int wtm) {
108	pmbaty	848	int score_mg, score_eg, majors, minors;
33	pmbaty	849
		850	/*
108	pmbaty	851	*************************************************************
		852	* *
		853	* We start with the raw Material balance for the current *
		854	* position, then adjust this with a small bonus for the *
		855	* side on move. *
		856	* *
		857	*************************************************************
33	pmbaty	858	*/
		859	score_mg = Material + ((wtm) ? wtm_bonus[mg] : -wtm_bonus[mg]);
		860	score_eg = Material + ((wtm) ? wtm_bonus[eg] : -wtm_bonus[eg]);
		861	/*
108	pmbaty	862	*************************************************************
		863	* *
		864	* test 1. if Majors or Minors are not balanced, then if *
		865	* one side is only an exchange up or down, we give a *
		866	* penalty to the side that is an exchange down, but not as *
		867	* big a penalty as the bad trade case below. *
		868	* *
		869	* test 2. if Majors or Minors are not balanced, then if *
		870	* one side has more piece material points than the other *
		871	* (using normal piece values of 3, 3, 5, 9 for N, B, R *
		872	* and Q) then the side that is behind in piece material *
		873	* gets a penalty. *
		874	* *
		875	*************************************************************
33	pmbaty	876	*/
108	pmbaty	877	majors =
		878	TotalPieces(white, rook) + 2 * TotalPieces(white,
		879	queen) - TotalPieces(black, rook) - 2 * TotalPieces(black, queen);
		880	minors =
		881	TotalPieces(white, knight) + TotalPieces(white,
		882	bishop) - TotalPieces(black, knight) - TotalPieces(black, bishop);
		883	if (majors \|\| minors) {
		884	if (Abs(TotalPieces(white, occupied) - TotalPieces(black, occupied)) != 2
		885	&& TotalPieces(white, occupied) - TotalPieces(black, occupied) != 0) {
		886	score_mg +=
		887	Sign(TotalPieces(white, occupied) - TotalPieces(black,
		888	occupied)) * bad_trade;
		889	score_eg +=
		890	Sign(TotalPieces(white, occupied) - TotalPieces(black,
		891	occupied)) * bad_trade;
33	pmbaty	892	}
		893	}
		894	tree->score_mg += score_mg;
		895	tree->score_eg += score_eg;
		896	}
		897
108	pmbaty	898	/* last modified 11/27/15 */
33	pmbaty	899	/*
		900	*******************************************************************************
		901	* *
		902	* EvaluatePassedPawns() is used to evaluate passed pawns and the danger *
108	pmbaty	903	* they produce. This code considers pieces as well, so it MUST NOT be done *
		904	* in the normal EvaluatePawns() code since that hashes information based *
		905	* only on the position of pawns. *
33	pmbaty	906	* *
108	pmbaty	907	* This is a significant rewrite of passed pawn evaluation, with the primary *
		908	* change being to collect the passed pawn scoring into one place, rather *
		909	* than have it scattered around all over the place. One example is the old *
		910	* rook_behind_passed_pawn scoring term that was done in rook scoring. It *
		911	* is now done here along with other passed pawn terms such as blockaded and *
		912	* the ability to advance or not. *
		913	* *
33	pmbaty	914	*******************************************************************************
		915	*/
		916	void EvaluatePassedPawns(TREE * RESTRICT tree, int side, int wtm) {
108	pmbaty	917	uint64_t behind, forward, backward, attacked, defended, thispawn;
		918	int file, square, score, score_mg = 0, score_eg = 0, next_sq;
		919	int pawns, rank, mg_base, eg_base, bonus, enemy = Flip(side);
		920	uint64_t fsliders = Queens(side) \| Rooks(side);
		921	uint64_t esliders = Queens(enemy) \| Rooks(enemy);
33	pmbaty	922
		923	/*
		924	************************************************************
		925	* *
108	pmbaty	926	* Initialize. The base value "passed_pawn[rank]" is *
		927	* almost the "square" of the rank. That got a bit too *
		928	* big, so a hand-tuned set of values, one per rank, *
		929	* proved to be a better value. *
33	pmbaty	930	* *
		931	************************************************************
		932	*/
		933	for (pawns = tree->pawn_score.passed[side]; pawns; pawns &= pawns - 1) {
		934	file = LSB8Bit(pawns);
108	pmbaty	935	thispawn = Pawns(side) & file_mask[file];
		936	if (thispawn) {
		937	square = MostAdvanced(side, thispawn);
		938	rank = rankflip[side][Rank(square)];
		939	score = passed_pawn[rank];
33	pmbaty	940	/*
		941	************************************************************
		942	* *
108	pmbaty	943	* For endgame only, we add in a bonus based on how close *
		944	* our king is to this pawn and a penalty based on how *
		945	* close the enemy king is. We also try to keep our king *
		946	* ahead of the pawn so it can escort it to promotion. We *
		947	* only do this for passed pawns whose base score value is *
		948	* greater than zero (ie pawns on ranks 4-7 since those *
		949	* are the ones threatening to become a major problem.) *
		950	* Also, if you happen to think that a small bonus for a *
		951	* passed pawn on the 3rd rank might be useful, consider *
		952	* speed. If the 3rd rank score is non-zero, that will *
		953	* trigger a significant amount of work below. In testing *
		954	* the additional cost more than offset the gain and so it *
		955	* is basically ignored unless rank > 3. *
		956	* *
33	pmbaty	957	************************************************************
		958	*/
108	pmbaty	959	if (score) {
		960	mg_base = score * passed_pawn_base[mg];
		961	eg_base = score * passed_pawn_base[eg];
		962	next_sq = square + direction[side];
		963	eg_base +=
		964	Distance(KingSQ(enemy),
		965	next_sq) * 2 * score - Distance(KingSQ(side), next_sq) * score;
		966	if (rank < RANK7)
		967	eg_base -=
		968	Distance(KingSQ(side), next_sq + direction[side]) * score / 2;
33	pmbaty	969	/*
		970	************************************************************
		971	* *
108	pmbaty	972	* If the pawn is not blockaded, we need to see whether it *
		973	* can actually advance or not. Note that this directly *
		974	* gives a bonus for blockading a passed pawn since the *
		975	* mobility evaluation below will not be applied when the *
		976	* pawn is blockaded by any piece. *
33	pmbaty	977	* *
108	pmbaty	978	* Step one is to determine if the squares in front of the *
		979	* pawn are attacked by the enemy. If not, we add in a *
		980	* significant score bonus. If some are attacked, we look *
		981	* to see if at least the square directly in front of the *
		982	* pawn is not attacked so that we can advance one square, *
		983	* anyway. This gets a smaller score bonus. *
33	pmbaty	984	* *
		985	************************************************************
		986	*/
108	pmbaty	987	if (!(OccupiedSquares & SetMask(next_sq))) {
		988	bonus = 0;
		989	if (Pawns(side) & pawn_attacks[enemy][next_sq])
		990	bonus = passed_pawn_free_advance;
		991	else {
		992	attacked = 0;
		993	forward = (side) ? plus8dir[square] : minus8dir[square];
		994	backward = (side) ? minus8dir[square] : plus8dir[square];
		995	if ((behind = backward & esliders) &&
		996	(FileAttacks(square) & behind))
		997	attacked = forward;
		998	else
		999	attacked = Attacked(tree, enemy, forward);
		1000	if (!attacked)
		1001	bonus = passed_pawn_free_advance;
		1002	else if (!(attacked & SetMask(next_sq)))
		1003	bonus = passed_pawn_free_advance_1;
33	pmbaty	1004	/*
		1005	************************************************************
		1006	* *
108	pmbaty	1007	* Step two is to determine if the squares in front of the *
		1008	* pawn are are defended by the friendly side. If all are *
		1009	* defended (such as with a rook or queen behind the pawn *
		1010	* or the king in front and to one side of the pawn, then *
		1011	* we give a bonus (but smaller than the previous cases). *
		1012	* As a last resort, if we at least defend the square in *
		1013	* front of the pawn, we give a small bonus. *
33	pmbaty	1014	* *
		1015	************************************************************
		1016	*/
108	pmbaty	1017	if ((behind = backward & fsliders) &&
		1018	(FileAttacks(square) & behind))
		1019	defended = forward;
		1020	else
		1021	defended = Attacked(tree, side, forward);
		1022	if (defended == forward)
		1023	bonus += passed_pawn_defended;
		1024	else if (defended & SetMask(next_sq))
		1025	bonus += passed_pawn_defended_1;
		1026	}
33	pmbaty	1027	/*
		1028	************************************************************
		1029	* *
108	pmbaty	1030	* Fold in the bonus for this pawn and move on to the next *
		1031	* (if there is one). Note that the bonus computed above *
		1032	* is multiplied by the base passed pawn score for this *
		1033	* particular rank. *
33	pmbaty	1034	* *
		1035	************************************************************
		1036	*/
108	pmbaty	1037	mg_base += bonus * score;
		1038	eg_base += bonus * score;
		1039	}
		1040	score_mg += mg_base;
		1041	score_eg += eg_base;
		1042	} else
		1043	score_eg += 4;
33	pmbaty	1044	}
		1045	}
		1046	/*
		1047	************************************************************
		1048	* *
108	pmbaty	1049	* All pawns done, add score to the two evaluation values *
		1050	* and return. *
33	pmbaty	1051	* *
		1052	************************************************************
		1053	*/
		1054	tree->score_mg += sign[side] * score_mg;
		1055	tree->score_eg += sign[side] * score_eg;
		1056	}
		1057
108	pmbaty	1058	/* last modified 11/27/15 */
33	pmbaty	1059	/*
		1060	*******************************************************************************
		1061	* *
		1062	* EvaluatePassedPawnRaces() is used to evaluate passed pawns when one *
		1063	* side has passed pawns and the other side (or neither) has pieces. In *
108	pmbaty	1064	* such a case, the critical question is can the defending king stop the *
		1065	* pawn from queening or is it too far away? If only one side has pawns *
		1066	* that can "run" then the situation is simple. When both sides have pawns *
		1067	* that can "run" it becomes more complex as it then becomes necessary to *
		1068	* see if one side can use a forced king move to stop the other side, while *
		1069	* the other side doesn't have the same ability to stop ours. *
33	pmbaty	1070	* *
		1071	* In the case of king and pawn endings with exactly one pawn, the simple *
		1072	* evaluation rules are used: if the king is two squares in front of the *
		1073	* pawn then it is a win, if the king is one one square in front with the *
		1074	* opposition, then it is a win, if the king is on the 6th rank with the *
		1075	* pawn close by, it is a win. Rook pawns are handled separately and are *
		1076	* more difficult to queen because the king can get trapped in front of the *
		1077	* pawn blocking promotion. *
		1078	* *
		1079	*******************************************************************************
		1080	*/
		1081	void EvaluatePassedPawnRaces(TREE * RESTRICT tree, int wtm) {
108	pmbaty	1082	uint64_t pawns, thispawn;
		1083	int file, square, queen_distance, pawnsq, passed, side, enemy;
33	pmbaty	1084	int queener[2] = { 8, 8 };
		1085	/*
		1086	************************************************************
		1087	* *
		1088	* Check to see if side has one pawn and neither side has *
		1089	* any pieces. If so, use the simple pawn evaluation *
		1090	* logic. *
		1091	* *
		1092	************************************************************
		1093	*/
		1094	for (side = black; side <= white; side++) {
		1095	enemy = Flip(side);
		1096	if (Pawns(side) && !Pawns(enemy) && TotalPieces(white, occupied) == 0 &&
		1097	TotalPieces(black, occupied) == 0) {
		1098	for (pawns = Pawns(side); pawns; pawns &= pawns - 1) {
		1099	pawnsq = LSB(pawns);
		1100	/*
		1101	************************************************************
		1102	* *
		1103	* King must be in front of the pawn or we go no further. *
		1104	* *
		1105	************************************************************
		1106	*/
		1107	if (sign[side] * Rank(KingSQ(side)) <= sign[side] * Rank(pawnsq))
		1108	continue;
		1109	/*
		1110	************************************************************
		1111	* *
		1112	* First a special case. If this is a rook pawn, then the *
		1113	* king must be on the adjacent file, and be closer to the *
		1114	* queening square than the opposing king. *
		1115	* *
		1116	************************************************************
		1117	*/
		1118	if (File(pawnsq) == FILEA) {
		1119	if (File(KingSQ(side)) == FILEB &&
		1120	Distance(KingSQ(side),
		1121	sqflip[side][A8]) < Distance(KingSQ(enemy),
		1122	sqflip[side][A8])) {
		1123	tree->score_eg += sign[side] * pawn_can_promote;
		1124	return;
		1125	}
		1126	continue;
		1127	} else if (File(pawnsq) == FILEH) {
		1128	if (File(KingSQ(side)) == FILEG &&
		1129	Distance(KingSQ(side),
		1130	sqflip[side][H8]) < Distance(KingSQ(enemy),
		1131	sqflip[side][H8])) {
		1132	tree->score_eg += sign[side] * pawn_can_promote;
		1133	return;
		1134	}
		1135	continue;
		1136	}
		1137	/*
		1138	************************************************************
		1139	* *
		1140	* If king is two squares in front of the pawn then it's a *
		1141	* win immediately. If the king is on the 6th rank and *
		1142	* closer to the pawn than the opposing king, it's also a *
		1143	* win. *
		1144	* *
		1145	************************************************************
		1146	*/
		1147	if (Distance(KingSQ(side), pawnsq) < Distance(KingSQ(enemy), pawnsq)) {
		1148	if (sign[side] * Rank(KingSQ(side)) >
		1149	sign[side] * (Rank(pawnsq) - 1 + 2 * side)) {
		1150	tree->score_eg += sign[side] * pawn_can_promote;
		1151	return;
		1152	}
108	pmbaty	1153	if (Rank(KingSQ(side)) == rank6[side]) {
33	pmbaty	1154	tree->score_eg += sign[side] * pawn_can_promote;
		1155	return;
		1156	}
		1157	/*
		1158	************************************************************
		1159	* *
		1160	* Last chance: if the king is one square in front of the *
		1161	* pawn and has the opposition, then it's still a win. *
		1162	* *
		1163	************************************************************
		1164	*/
		1165	if (Rank(KingSQ(side)) == Rank(pawnsq) - 1 + 2 * side &&
		1166	EvaluateHasOpposition(wtm == side, KingSQ(side),
		1167	KingSQ(enemy))) {
		1168	tree->score_eg += sign[side] * pawn_can_promote;
		1169	return;
		1170	}
		1171	}
		1172	}
		1173	}
		1174	/*
		1175	************************************************************
		1176	* *
		1177	* Check to see if enemy is out of pieces and stm has *
		1178	* passed pawns. If so, see if any of these passed pawns *
		1179	* can outrun the defending king and promote. *
		1180	* *
		1181	************************************************************
		1182	*/
		1183	if (TotalPieces(enemy, occupied) == 0 && tree->pawn_score.passed[side]) {
		1184	passed = tree->pawn_score.passed[side];
		1185	for (; passed; passed &= passed - 1) {
		1186	file = LSB8Bit(passed);
108	pmbaty	1187	thispawn = Pawns(side) & file_mask[file];
		1188	if (thispawn) {
		1189	square = MostAdvanced(side, thispawn);
		1190	if (!(pawn_race[side][wtm][square] & Kings(enemy))) {
		1191	queen_distance = Abs(rank8[side] - Rank(square));
		1192	if (Kings(side) & ((side) ? plus8dir[square] : minus8dir[square])) {
		1193	if (file == FILEA \|\| file == FILEH)
		1194	queen_distance = 99;
		1195	queen_distance++;
		1196	}
		1197	if (Rank(square) == rank2[side])
		1198	queen_distance--;
		1199	if (queen_distance < queener[side])
		1200	queener[side] = queen_distance;
33	pmbaty	1201	}
		1202	}
		1203	}
		1204	}
		1205	}
		1206	/*
		1207	************************************************************
		1208	* *
		1209	* Now that we know which pawns can outrun the kings for *
108	pmbaty	1210	* each side, we need to do determine if one side queens *
		1211	* before the other. If so, that side wins. If they *
		1212	* queen at the same time, then we will have to rely on *
		1213	* the search to handle queening with check or queening *
		1214	* and attacking the opponent's queening square. *
33	pmbaty	1215	* *
		1216	************************************************************
		1217	*/
108	pmbaty	1218	if (queener[white] < queener[black])
33	pmbaty	1219	tree->score_eg += pawn_can_promote + (5 - queener[white]) * 10;
108	pmbaty	1220	else if (queener[black] < queener[white])
		1221	tree->score_eg -= pawn_can_promote + (5 - queener[black]) * 10;
33	pmbaty	1222	}
		1223
108	pmbaty	1224	/* last modified 11/27/15 */
33	pmbaty	1225	/*
		1226	*******************************************************************************
		1227	* *
		1228	* EvaluatePawns() is used to evaluate pawns. It evaluates pawns for only *
		1229	* one side, and fills in the pawn hash entry information. It requires two *
		1230	* calls to evaluate all pawns on the board. Comments below indicate the *
		1231	* particular pawn structure features that are evaluated. *
		1232	* *
108	pmbaty	1233	* This procedure also flags which pawns are passed, since this is scored in *
		1234	* another part of the evaluation because that includes piece information *
		1235	* which can not be used here since the pawn hash signature does not include *
		1236	* piece information of any kind. *
33	pmbaty	1237	* *
108	pmbaty	1238	* Note that a pawn is not penalized for two different reasons. If it is *
		1239	* isolated, it is not backward. Etc. This simplifies evaluation tuning *
		1240	* not to mention eliminating the overlap and interaction that was happening *
		1241	* previously when multiple penalties could be applied. *
		1242	* *
33	pmbaty	1243	*******************************************************************************
		1244	*/
		1245	void EvaluatePawns(TREE * RESTRICT tree, int side) {
108	pmbaty	1246	uint64_t pawns, attackers, defenders;
		1247	uint64_t doubled, supported, connected, passed, backward;
		1248	int square, file, rank, score_eg = 0, score_mg = 0, enemy = Flip(side);
		1249	unsigned int isolated, pawn_files = 0;
33	pmbaty	1250
		1251	/*
		1252	************************************************************
		1253	* *
108	pmbaty	1254	* Loop through all pawns for this side. *
33	pmbaty	1255	* *
		1256	************************************************************
		1257	*/
		1258	tree->pawn_score.passed[side] = 0;
		1259	for (pawns = Pawns(side); pawns; pawns &= pawns - 1) {
		1260	square = LSB(pawns);
		1261	file = File(square);
		1262	rank = rankflip[side][Rank(square)];
108	pmbaty	1263	pawn_files \|= 1 << file;
33	pmbaty	1264	/*
		1265	************************************************************
		1266	* *
		1267	* Evaluate pawn advances. Center pawns are encouraged to *
108	pmbaty	1268	* occupy central squares, edge pawns are penalized on all *
		1269	* edge squares to encourage capture toward the center, *
		1270	* the rest are neutral. *
33	pmbaty	1271	* *
		1272	************************************************************
		1273	*/
154	pmbaty	1274	score_mg += pval[side][square];
33	pmbaty	1275	/*
		1276	************************************************************
		1277	* *
108	pmbaty	1278	* Evaluate isolated pawns, which are penalized based on *
		1279	* which file they occupy. *
33	pmbaty	1280	* *
		1281	************************************************************
		1282	*/
108	pmbaty	1283	isolated = !(Pawns(side) & mask_pawn_isolated[square]);
		1284	if (isolated) {
		1285	score_mg -= pawn_isolated[mg][file];
		1286	score_eg -= pawn_isolated[eg][file];
33	pmbaty	1287	}
		1288	/*
		1289	************************************************************
		1290	* *
108	pmbaty	1291	* Evaluate unsupported pawns, which provide a target *
		1292	* since they are undefended by a pawn. We exclude pawns *
		1293	* that are isolated since they have already been given a *
		1294	* penalty. *
33	pmbaty	1295	* *
		1296	************************************************************
		1297	*/
108	pmbaty	1298	supported = Pawns(side) & pawn_attacks[enemy][square];
		1299	if (!isolated && !supported) {
		1300	score_mg += pawn_unsupported[mg];
		1301	score_eg += pawn_unsupported[eg];
		1302	}
33	pmbaty	1303	/*
		1304	************************************************************
		1305	* *
108	pmbaty	1306	* Evaluate doubled pawns. If there are other pawns on *
		1307	* this file in front of this pawn, penalize this pawn. *
		1308	* Note that this will NOT penalize both pawns, just the *
		1309	* most rearward one that is really almost worthless. *
33	pmbaty	1310	* *
108	pmbaty	1311	* The farther apart two doubled pawns (same file) are, *
		1312	* the less weak they are, so the penalty is reduced as *
		1313	* this distance increases. *
		1314	* *
33	pmbaty	1315	************************************************************
		1316	*/
108	pmbaty	1317	doubled = Pawns(side) & ((side) ? plus8dir[square] : minus8dir[square]);
		1318	if (doubled) {
		1319	score_mg -=
		1320	pawn_doubled[mg][file] / RankDistance(square, MostAdvanced(side,
		1321	doubled));
		1322	score_eg -=
		1323	pawn_doubled[eg][file] / RankDistance(square, MostAdvanced(side,
		1324	doubled));
		1325	}
33	pmbaty	1326	/*
		1327	************************************************************
		1328	* *
108	pmbaty	1329	* Test the pawn to see if it is connected to a neighbor *
		1330	* which makes it easier to defend. *
33	pmbaty	1331	* *
		1332	************************************************************
		1333	*/
108	pmbaty	1334	connected = Pawns(side) & mask_pawn_connected[side][square];
		1335	if (connected) {
154	pmbaty	1336	score_mg += pawn_connected[mg][rank][file];
		1337	score_eg += pawn_connected[eg][rank][file];
108	pmbaty	1338	}
33	pmbaty	1339	/*
		1340	************************************************************
		1341	* *
108	pmbaty	1342	* Flag passed pawns for use later when we finally call *
		1343	* EvaluatePassedPawns. *
33	pmbaty	1344	* *
		1345	************************************************************
		1346	*/
108	pmbaty	1347	passed = !(Pawns(enemy) & mask_passed[side][square]);
		1348	if (passed)
		1349	tree->pawn_score.passed[side] \|= 1 << file;
33	pmbaty	1350	/*
		1351	************************************************************
		1352	* *
108	pmbaty	1353	* Test the pawn to see if it is backward which makes it a *
		1354	* target that ties down pieces to defend it. *
33	pmbaty	1355	* *
		1356	************************************************************
		1357	*/
108	pmbaty	1358	backward = 0;
		1359	if (!(passed \| isolated \| connected \| (Pawns(side) &
		1360	mask_pattacks[side][square]) \| (Pawns(enemy) &
		1361	PawnAttacks(side, square))))
		1362	backward = Pawns(enemy) & PawnAttacks(side, square + direction[side]);
		1363	if (backward) {
		1364	score_mg -= pawn_backward[mg][file];
		1365	score_eg -= pawn_backward[eg][file];
		1366	}
33	pmbaty	1367	/*
		1368	************************************************************
		1369	* *
108	pmbaty	1370	* Determine if this pawn is a candidate passed pawn, *
		1371	* which is a pawn on a file with no enemy pawns in front *
		1372	* of it, and if it advances until it contacts an enemy *
		1373	* pawn, and it is defended at least as many times as it *
		1374	* is attacked when it reaches that pawn, then it will end *
		1375	* up passed. *
33	pmbaty	1376	* *
		1377	************************************************************
		1378	*/
108	pmbaty	1379	if (!(passed \| backward \| isolated) &&
		1380	!(Pawns(enemy) & ((side) ? plus8dir[square] : minus8dir[square]))) {
		1381	defenders = mask_pattacks[side][square + direction[side]] & Pawns(side);
		1382	attackers = mask_pattacks[enemy][square] & Pawns(enemy);
		1383	if (PopCnt(defenders) >= PopCnt(attackers)) {
		1384	score_mg += passed_pawn_candidate[mg][rank];
		1385	score_eg += passed_pawn_candidate[eg][rank];
33	pmbaty	1386	}
		1387	}
108	pmbaty	1388	}
33	pmbaty	1389	/*
		1390	************************************************************
		1391	* *
108	pmbaty	1392	* Give a bonus for distance between left-most pawn and *
		1393	* right-most pawn. The idea is that the wider the gap *
		1394	* between the pawns, the harder they are for a lone king *
		1395	* to control in the endgame. Botvinnik referred to this *
		1396	* concept as "trousers" (pants with two legs, the farther *
		1397	* the legs are apart, the better for the side with those *
		1398	* pawns). *
33	pmbaty	1399	* *
		1400	************************************************************
		1401	*/
108	pmbaty	1402	score_eg += pawn_file_width * (MSB8Bit(pawn_files) - LSB8Bit(pawn_files));
33	pmbaty	1403	/*
		1404	************************************************************
		1405	* *
		1406	* Evaluate king safety. *
		1407	* *
108	pmbaty	1408	* This uses the function EvaluateKingsFile() and looks at *
		1409	* three possible positions for the king, either castled *
33	pmbaty	1410	* kingside, queenside or else standing on the d or e file *
		1411	* stuck in the middle. This essentially is about the *
		1412	* pawns in front of the king and what kind of "shelter" *
		1413	* they provide for the king during the middlegame. *
		1414	* *
		1415	************************************************************
		1416	*/
108	pmbaty	1417	tree->pawn_score.defects_q[side] =
		1418	EvaluateKingsFile(tree, side, FILEA, FILEC);
		1419	tree->pawn_score.defects_m[side] =
		1420	EvaluateKingsFile(tree, side, FILEC, FILEF);
		1421	tree->pawn_score.defects_k[side] =
		1422	EvaluateKingsFile(tree, side, FILEF, FILEH);
		1423	/*
		1424	************************************************************
		1425	* *
		1426	* Done. Add mg/eg scores to final result (sign-corrected *
		1427	* so that black = -, white = +) and return. *
		1428	* *
		1429	************************************************************
		1430	*/
33	pmbaty	1431	tree->pawn_score.score_mg += sign[side] * score_mg;
		1432	tree->pawn_score.score_eg += sign[side] * score_eg;
		1433	}
		1434
108	pmbaty	1435	/* last modified 10/19/15 */
33	pmbaty	1436	/*
		1437	*******************************************************************************
		1438	* *
		1439	* EvaluateQueens() is used to evaluate queens. *
		1440	* *
		1441	*******************************************************************************
		1442	*/
		1443	void EvaluateQueens(TREE * RESTRICT tree, int side) {
		1444	uint64_t temp;
108	pmbaty	1445	int square, i, score_mg = 0, score_eg = 0, enemy = Flip(side);
33	pmbaty	1446
		1447	/*
		1448	************************************************************
		1449	* *
		1450	* First locate each queen and obtain it's centralization *
		1451	* score from the static piece/square table for queens. *
		1452	* *
		1453	************************************************************
		1454	*/
		1455	for (temp = Queens(side); temp; temp &= temp - 1) {
		1456	square = LSB(temp);
		1457	/*
		1458	************************************************************
		1459	* *
		1460	* Then, add in the piece/square table value for the *
		1461	* queen. *
		1462	* *
		1463	************************************************************
		1464	*/
		1465	score_mg += qval[mg][side][square];
		1466	score_eg += qval[eg][side][square];
		1467	/*
		1468	************************************************************
		1469	* *
		1470	* Adjust the tropism count for this piece. *
		1471	* *
		1472	************************************************************
		1473	*/
		1474	if (tree->dangerous[side]) {
108	pmbaty	1475	i = KingSQ(enemy);
		1476	tree->tropism[side] += king_tropism_q[Distance(square, i)];
		1477	i = 8 - (RankDistance(square, i) + FileDistance(square, i));
		1478	score_mg += i;
		1479	score_eg += i;
33	pmbaty	1480	}
		1481	}
		1482	tree->score_mg += sign[side] * score_mg;
		1483	tree->score_eg += sign[side] * score_eg;
		1484	}
		1485
108	pmbaty	1486	/* last modified 10/19/15 */
33	pmbaty	1487	/*
		1488	*******************************************************************************
		1489	* *
		1490	* EvaluateRooks() is used to evaluate rooks. *
		1491	* *
		1492	*******************************************************************************
		1493	*/
		1494	void EvaluateRooks(TREE * RESTRICT tree, int side) {
		1495	uint64_t temp, moves;
108	pmbaty	1496	int square, rank, file, i, mobility, score_mg = 0, score_eg = 0;
33	pmbaty	1497	int enemy = Flip(side);
		1498
		1499	/*
		1500	************************************************************
		1501	* *
		1502	* Initialize. *
		1503	* *
		1504	************************************************************
		1505	*/
		1506	for (temp = Rooks(side); temp; temp &= temp - 1) {
		1507	square = LSB(temp);
		1508	file = File(square);
		1509	rank = Rank(square);
		1510	/*
		1511	************************************************************
		1512	* *
		1513	* Determine if the rook is on an open file or on a half- *
		1514	* open file, either of which increases its ability to *
		1515	* attack important squares. *
		1516	* *
		1517	************************************************************
		1518	*/
		1519	if (!(file_mask[file] & Pawns(side))) {
		1520	if (!(file_mask[file] & Pawns(enemy))) {
		1521	score_mg += rook_open_file[mg];
		1522	score_eg += rook_open_file[eg];
		1523	} else {
		1524	score_mg += rook_half_open_file[mg];
		1525	score_eg += rook_half_open_file[eg];
		1526	}
		1527	}
		1528	/*
		1529	************************************************************
		1530	* *
108	pmbaty	1531	* Mobility counts the number of squares the rook attacks, *
		1532	* excluding squares with friendly pieces, and weighs each *
		1533	* square according to a complex formula that includes *
		1534	* files as well as total number of squares attacked. *
		1535	* *
		1536	************************************************************
		1537	*/
		1538	mobility = RookMobility(square, OccupiedSquares);
		1539	score_mg += mobility;
		1540	score_eg += mobility;
		1541	/*
		1542	************************************************************
		1543	* *
33	pmbaty	1544	* Check to see if the king has been forced to move and *
		1545	* has trapped a rook at a1/b1/g1/h1, if so, then penalize *
108	pmbaty	1546	* the trapped rook to help extricate it. We only need to *
		1547	* check this if the rooks mobility is very low. *
33	pmbaty	1548	* *
		1549	************************************************************
		1550	*/
108	pmbaty	1551	if (mobility < 0 && rank == rank1[side] && rank == Rank(KingSQ(side))) {
		1552	i = File(KingSQ(side));
		1553	if (i > FILEE) {
		1554	if (file > i) {
		1555	score_mg += mobility * 3;
		1556	score_eg += mobility * 3;
33	pmbaty	1557	}
108	pmbaty	1558	} else if (i < FILED && file < i) {
		1559	score_mg += mobility * 3;
		1560	score_eg += mobility * 3;
33	pmbaty	1561	}
		1562	}
		1563	/*
		1564	************************************************************
		1565	* *
108	pmbaty	1566	* finally check to see if any rooks are on the 7th rank, *
		1567	* with the opponent having pawns on that rank or the *
		1568	* opponent's king being hemmed in on the 7th/8th rank. *
		1569	* If so, we give a bonus for the strong rook. If there *
		1570	* is another rook or queen on the 7th that is connected *
		1571	* with this one, then the positional advantage is even *
		1572	* stronger. *
33	pmbaty	1573	* *
		1574	************************************************************
		1575	*/
108	pmbaty	1576	else if (rank == rank7[side] && (Rank(KingSQ(enemy)) == rank8[side]
		1577	\|\| Pawns(enemy) & rank_mask[rank])) {
33	pmbaty	1578	score_mg += rook_on_7th[mg];
		1579	score_eg += rook_on_7th[eg];
108	pmbaty	1580	if (RankAttacks(square) & (Queens(side) \| Rooks(side))) {
		1581	score_mg += rook_connected_7th[mg];
		1582	score_eg += rook_connected_7th[eg];
		1583	}
33	pmbaty	1584	}
		1585	/*
		1586	************************************************************
		1587	* *
		1588	* Adjust the tropism count for this piece. *
		1589	* *
		1590	************************************************************
		1591	*/
		1592	if (tree->dangerous[side]) {
		1593	moves = king_attacks[KingSQ(enemy)];
108	pmbaty	1594	i = (rook_attacks[square] & moves &&
33	pmbaty	1595	RookAttacks(square,
108	pmbaty	1596	OccupiedSquares & ~(Queens(side) \| Rooks(side))) & moves) ? 1 :
		1597	Distance(square, KingSQ(enemy));
		1598	tree->tropism[side] += king_tropism_r[i];
33	pmbaty	1599	}
		1600	}
		1601	tree->score_mg += sign[side] * score_mg;
		1602	tree->score_eg += sign[side] * score_eg;
		1603	}
		1604
108	pmbaty	1605	/* last modified 01/03/15 */
33	pmbaty	1606	/*
		1607	*******************************************************************************
		1608	* *
		1609	* EvaluateWinningChances() is used to determine if one side has reached a *
		1610	* position which can not be won, period, even though side may be ahead in *
		1611	* material in some way. *
		1612	* *
		1613	* Return values: *
108	pmbaty	1614	* 0 -> side on move can not win. *
		1615	* 1 -> side on move can win. *
33	pmbaty	1616	* *
		1617	*******************************************************************************
		1618	*/
		1619	int EvaluateWinningChances(TREE * RESTRICT tree, int side, int wtm) {
108	pmbaty	1620	int square, ekd, promote, majors, minors, enemy = Flip(side);
33	pmbaty	1621
108	pmbaty	1622	if (!Pawns(side)) {
33	pmbaty	1623	/*
		1624	************************************************************
		1625	* *
		1626	* If side has a piece and no pawn, it can not possibly *
		1627	* win. If side is a piece ahead, the only way it can win *
		1628	* is if the enemy is already trapped on the edge of the *
		1629	* board (special case to handle KRB vs KR which can be *
		1630	* won if the king gets trapped). *
		1631	* *
		1632	************************************************************
		1633	*/
		1634	if (TotalPieces(side, occupied) <= 3)
		1635	return 0;
		1636	if (TotalPieces(side, occupied) - TotalPieces(enemy, occupied) <= 3 &&
		1637	mask_not_edge & Kings(enemy))
		1638	return 0;
108	pmbaty	1639	/*
		1640	************************************************************
		1641	* *
		1642	* If one side is an exchange up, but has no pawns, then *
		1643	* that side can not possibly win. *
		1644	* *
		1645	************************************************************
		1646	*/
		1647	majors =
		1648	TotalPieces(white, rook) + 2 * TotalPieces(white,
		1649	queen) - TotalPieces(black, rook) - 2 * TotalPieces(black, queen);
		1650	if (Abs(majors) == 1) {
		1651	minors =
		1652	TotalPieces(black, knight) + TotalPieces(black,
		1653	bishop) - TotalPieces(white, knight) - TotalPieces(white, bishop);
		1654	if (majors == minors)
		1655	return 0;
		1656	}
		1657	} else {
		1658	/*
		1659	************************************************************
		1660	* *
		1661	* If neither side has any pieces, and both sides have *
		1662	* non-rookpawns, then either side can win. *
		1663	* *
		1664	************************************************************
		1665	*/
		1666	if (TotalPieces(white, occupied) == 0 && TotalPieces(black, occupied) == 0
		1667	&& Pawns(white) & not_rook_pawns && Pawns(black) & not_rook_pawns)
		1668	return 1;
33	pmbaty	1669	}
		1670	/*
		1671	************************************************************
		1672	* *
		1673	* If "side" has a pawn, then either the pawn had better *
108	pmbaty	1674	* not be a rook pawn, or else side had better have the *
33	pmbaty	1675	* right color bishop or any other piece, otherwise it is *
		1676	* not winnable if the enemy king can get to the queening *
		1677	* square first. *
		1678	* *
		1679	************************************************************
		1680	*/
108	pmbaty	1681	if (!(Pawns(side) & not_rook_pawns))
33	pmbaty	1682	do {
		1683	if (TotalPieces(side, occupied) > 3 \|\| (TotalPieces(side, occupied) == 3
		1684	&& Knights(side)))
		1685	continue;
		1686	if (file_mask[FILEA] & Pawns(side) && file_mask[FILEH] & Pawns(side))
		1687	continue;
		1688	if (Bishops(side)) {
		1689	if (Bishops(side) & dark_squares) {
		1690	if (file_mask[dark_corner[side]] & Pawns(side))
		1691	continue;
		1692	} else if (file_mask[light_corner[side]] & Pawns(side))
		1693	continue;
		1694	}
		1695	if (Pawns(side) & file_mask[FILEA])
		1696	promote = A8;
		1697	else
		1698	promote = H8;
		1699	ekd = Distance(KingSQ(enemy), sqflip[side][promote]) - (wtm != side);
		1700	if (ekd <= 1)
		1701	return 0;
		1702	} while (0);
		1703	/*
		1704	************************************************************
		1705	* *
108	pmbaty	1706	* Check to see if this is a KRP vs KR ending. If so, and *
		1707	* the losing king is in front of the passer, then this is *
		1708	* a drawish ending. *
33	pmbaty	1709	* *
		1710	************************************************************
		1711	*/
		1712	if (TotalPieces(side, pawn) == 1 && TotalPieces(enemy, pawn) == 0 &&
108	pmbaty	1713	TotalPieces(side, occupied) == 5 && TotalPieces(enemy, occupied) == 5) {
33	pmbaty	1714	square = LSB(Pawns(side));
		1715	if (FileDistance(KingSQ(enemy), square) <= 1 &&
		1716	InFront(side, Rank(KingSQ(enemy)), Rank(square)))
		1717	return 0;
		1718	}
		1719	/*
		1720	************************************************************
		1721	* *
		1722	* If this side has pawns, and we have made it through the *
		1723	* previous tests, then this side has winning chances. *
		1724	* *
		1725	************************************************************
		1726	*/
		1727	if (TotalPieces(side, pawn))
		1728	return 1;
		1729	/*
		1730	************************************************************
		1731	* *
		1732	* If this side has two bishops, and the enemy has only a *
		1733	* single kinght, the two bishops win. *
		1734	* *
		1735	************************************************************
		1736	*/
		1737	if (TotalPieces(side, occupied) == 6)
		1738	if (TotalPieces(enemy, occupied) == 3 && (Knights(side)
		1739	\|\| !Knights(enemy)))
		1740	return 0;
		1741	/*
		1742	************************************************************
		1743	* *
		1744	* If one side is two knights ahead and the opponent has *
		1745	* no remaining material, it is a draw. *
		1746	* *
		1747	************************************************************
		1748	*/
		1749	if (TotalPieces(side, occupied) == 6 && !Bishops(side)
		1750	&& TotalPieces(enemy, occupied) + TotalPieces(enemy, pawn) == 0)
		1751	return 0;
108	pmbaty	1752	/*
		1753	************************************************************
		1754	* *
		1755	* If we make it through all the above tests, then "side" *
		1756	* can win so we return 1. *
		1757	* *
		1758	************************************************************
		1759	*/
33	pmbaty	1760	return 1;
		1761	}
108	pmbaty	1762
		1763	/*
		1764	*******************************************************************************
		1765	* *
		1766	* InitializeKingSafety() is used to initialize the king safety matrix. *
		1767	* This is set so that the matrix, indexed by king safety pawn structure *
		1768	* index and by king safety piece tropism, combines the two indices to *
		1769	* produce a single score. As either index rises, the king safety score *
		1770	* tracks along, but as both rise, the king safety score rises much more *
		1771	* quickly. *
		1772	* *
		1773	*******************************************************************************
		1774	*/
		1775	void InitializeKingSafety() {
		1776	int safety, tropism;
		1777
		1778	for (safety = 0; safety < 16; safety++) {
		1779	for (tropism = 0; tropism < 16; tropism++) {
		1780	king_safety[safety][tropism] =
		1781	180 * ((safety_vector[safety] + 100) * (tropism_vector[tropism] +
		1782	100) / 100 - 100) / 100;
		1783	}
		1784	}
		1785	}

Subversion Repositories Games.Chess Giants

Games.Chess Giants/engine-crafty/evaluate.c – Rev 156