testsAndMisc-archive/C/lichess_random_engine/micro_max.c
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2025-11-30 13:42:16 +01:00

751 lines
19 KiB
C

// Readable micro-Max (https://home.hccnet.nl/h.g.muller/max-src2.html) inspired engine:
// CLI-compatible with engine.py Usage:
// micro_max_engine [--seed N] [--fen FEN] [--explain] [--analyze UCI] <move1> <move2> ...
// Behavior: ranks provided UCI moves using a simple material/king-safety heuristic derived
// from the FEN position (if given). Prints chosen move by default, or JSON with --explain.
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
typedef struct
{
char squares[64]; // a1=0 .. h8=63, '.' empty, uppercase white, lowercase black
int white_to_move; // 1 white, 0 black
} Board;
static int file_of(int idx) { return idx % 8; }
static int rank_of(int idx) { return idx / 8; }
static int idx_from_fr(int f, int r) { return (r * 8) + f; }
static int on_board(int f, int r) { return f >= 0 && f < 8 && r >= 0 && r < 8; }
static int is_white(char p) { return p >= 'A' && p <= 'Z'; }
static int is_black(char p) { return p >= 'a' && p <= 'z'; }
static int piece_value_cp(char p)
{
switch (tolower((unsigned char)p))
{
case 'p':
return 100;
case 'n':
return 320;
case 'b':
return 330;
case 'r':
return 500;
case 'q':
return 900;
case 'k':
return 0;
default:
return 0;
}
}
static int parse_fen(Board *b, const char *fen)
{
memset(b->squares, '.', sizeof(b->squares));
b->white_to_move = 1;
if (!fen || !*fen)
{
return 0;
}
int f = 0;
int r = 7;
const char *p = fen;
while (*p && *p != ' ')
{
char c = *p++;
if (c == '/')
{
f = 0;
r--;
if (r < 0)
{
return 0;
}
continue;
}
if (c >= '1' && c <= '8')
{
f += (c - '0');
if (f > 8)
{
return 0;
}
continue;
}
if (isalpha((unsigned char)c))
{
if (f >= 8 || r < 0)
{
return 0;
}
b->squares[idx_from_fr(f, r)] = c;
f++;
}
else
{
return 0;
}
}
if (*p == ' ')
{
p++;
}
if (*p == 'w')
{
b->white_to_move = 1;
p++;
}
else if (*p == 'b')
{
b->white_to_move = 0;
p++;
}
return 1;
}
static int find_king(const Board *b, int white)
{
char k = white ? 'K' : 'k';
for (int i = 0; i < 64; ++i)
{
if (b->squares[i] == k)
{
return i;
}
}
return -1;
}
static int sq_attacked_by(const Board *b, int target_idx, int by_white)
{
int tf = file_of(target_idx);
int tr = rank_of(target_idx);
// Knights
const int kdf[8] = {1, 2, 2, 1, -1, -2, -2, -1};
const int kdr[8] = {2, 1, -1, -2, 2, 1, -1, -2};
for (int i = 0; i < 8; ++i)
{
int f = tf + kdf[i];
int r = tr + kdr[i];
if (on_board(f, r))
{
char p = b->squares[idx_from_fr(f, r)];
if (by_white ? p == 'N' : p == 'n')
{
return 1;
}
}
}
// King
for (int df = -1; df <= 1; ++df)
{
for (int dr = -1; dr <= 1; ++dr)
{
if (df || dr)
{
int f = tf + df;
int r = tr + dr;
if (on_board(f, r))
{
char p = b->squares[idx_from_fr(f, r)];
if (by_white ? p == 'K' : p == 'k')
{
return 1;
}
}
}
}
}
// Pawns
if (by_white)
{
int f1 = tf - 1;
int r1 = tr - 1;
int f2 = tf + 1;
int r2 = tr - 1;
if (on_board(f1, r1) && b->squares[idx_from_fr(f1, r1)] == 'P')
{
return 1;
}
if (on_board(f2, r2) && b->squares[idx_from_fr(f2, r2)] == 'P')
{
return 1;
}
}
else
{
int f1 = tf - 1;
int r1 = tr + 1;
int f2 = tf + 1;
int r2 = tr + 1;
if (on_board(f1, r1) && b->squares[idx_from_fr(f1, r1)] == 'p')
{
return 1;
}
if (on_board(f2, r2) && b->squares[idx_from_fr(f2, r2)] == 'p')
{
return 1;
}
}
// Bishops/queens
const int dsf[4] = {1, 1, -1, -1};
const int dsr[4] = {1, -1, 1, -1};
for (int d = 0; d < 4; ++d)
{
int f = tf + dsf[d];
int r = tr + dsr[d];
while (on_board(f, r))
{
char p = b->squares[idx_from_fr(f, r)];
if (p != '.')
{
if (by_white ? (p == 'B' || p == 'Q') : (p == 'b' || p == 'q'))
{
return 1;
}
break;
}
f += dsf[d];
r += dsr[d];
}
}
// Rooks/queens
const int rsf[4] = {1, -1, 0, 0};
const int rsr[4] = {0, 0, 1, -1};
for (int d = 0; d < 4; ++d)
{
int f = tf + rsf[d];
int r = tr + rsr[d];
while (on_board(f, r))
{
char p = b->squares[idx_from_fr(f, r)];
if (p != '.')
{
if (by_white ? (p == 'R' || p == 'Q') : (p == 'r' || p == 'q'))
{
return 1;
}
break;
}
f += rsf[d];
r += rsr[d];
}
}
return 0;
}
static int count_attackers(const Board *b, int target_idx, int by_white)
{
int tf = file_of(target_idx);
int tr = rank_of(target_idx);
int cnt = 0;
const int kdf[8] = {1, 2, 2, 1, -1, -2, -2, -1};
const int kdr[8] = {2, 1, -1, -2, 2, 1, -1, -2};
for (int i = 0; i < 8; ++i)
{
int f = tf + kdf[i];
int r = tr + kdr[i];
if (on_board(f, r))
{
char p = b->squares[idx_from_fr(f, r)];
if (by_white ? p == 'N' : p == 'n')
{
cnt++;
}
}
}
for (int df = -1; df <= 1; ++df)
{
for (int dr = -1; dr <= 1; ++dr)
{
if (df || dr)
{
int f = tf + df;
int r = tr + dr;
if (on_board(f, r))
{
char p = b->squares[idx_from_fr(f, r)];
if (by_white ? p == 'K' : p == 'k')
{
cnt++;
}
}
}
}
}
if (by_white)
{
int f1 = tf - 1;
int r1 = tr - 1;
int f2 = tf + 1;
int r2 = tr - 1;
if (on_board(f1, r1) && b->squares[idx_from_fr(f1, r1)] == 'P')
{
cnt++;
}
if (on_board(f2, r2) && b->squares[idx_from_fr(f2, r2)] == 'P')
{
cnt++;
}
}
else
{
int f1 = tf - 1;
int r1 = tr + 1;
int f2 = tf + 1;
int r2 = tr + 1;
if (on_board(f1, r1) && b->squares[idx_from_fr(f1, r1)] == 'p')
{
cnt++;
}
if (on_board(f2, r2) && b->squares[idx_from_fr(f2, r2)] == 'p')
{
cnt++;
}
}
const int dsf[4] = {1, 1, -1, -1};
const int dsr[4] = {1, -1, 1, -1};
for (int d = 0; d < 4; ++d)
{
int f = tf + dsf[d];
int r = tr + dsr[d];
while (on_board(f, r))
{
char p = b->squares[idx_from_fr(f, r)];
if (p != '.')
{
if (by_white ? (p == 'B' || p == 'Q') : (p == 'b' || p == 'q'))
{
cnt++;
}
break;
}
f += dsf[d];
r += dsr[d];
}
}
const int rsf[4] = {1, -1, 0, 0};
const int rsr[4] = {0, 0, 1, -1};
for (int d = 0; d < 4; ++d)
{
int f = tf + rsf[d];
int r = tr + rsr[d];
while (on_board(f, r))
{
char p = b->squares[idx_from_fr(f, r)];
if (p != '.')
{
if (by_white ? (p == 'R' || p == 'Q') : (p == 'r' || p == 'q'))
{
cnt++;
}
break;
}
f += rsf[d];
r += rsr[d];
}
}
return cnt;
}
static int material_cp(const Board *b)
{
int w = 0;
int bl = 0;
for (int i = 0; i < 64; ++i)
{
char p = b->squares[i];
if (p == '.')
{
continue;
}
int v = piece_value_cp(p);
if (is_white(p))
{
w += v;
}
else
{
bl += v;
}
}
return w - bl;
}
static int parse_uci(const char *uci, int *from, int *to, char *prom)
{
if (!uci || strlen(uci) < 4)
{
return 0;
}
int f1 = uci[0] - 'a';
int r1 = uci[1] - '1';
int f2 = uci[2] - 'a';
int r2 = uci[3] - '1';
if (!on_board(f1, r1) || !on_board(f2, r2))
{
return 0;
}
*from = idx_from_fr(f1, r1);
*to = idx_from_fr(f2, r2);
*prom = (uci[4] ? uci[4] : 0);
return 1;
}
static void apply_move(const Board *in, const char *uci, Board *out, int *cap_cp, int *prom_gain_cp)
{
*out = *in;
*cap_cp = 0;
*prom_gain_cp = 0;
int from;
int to;
char prom = 0;
if (!parse_uci(uci, &from, &to, &prom))
{
return;
}
char mover = out->squares[from];
char captured = out->squares[to];
if (captured != '.')
{
*cap_cp = piece_value_cp(captured);
}
out->squares[to] = mover;
out->squares[from] = '.';
if (prom)
{
int is_w = is_white(mover);
char p = (char)tolower((unsigned char)prom);
char prom_piece = p == 'q' ? (is_w ? 'Q' : 'q')
: p == 'r' ? (is_w ? 'R' : 'r')
: p == 'b' ? (is_w ? 'B' : 'b')
: (is_w ? 'N' : 'n');
int gain = piece_value_cp(prom_piece) - piece_value_cp(is_w ? 'P' : 'p');
*prom_gain_cp = gain;
out->squares[to] = prom_piece;
}
out->white_to_move = !in->white_to_move;
}
typedef struct
{
char uci[16];
double cap_cp;
double prom_cp;
double mat_cp;
double atk_opp_king;
double opp_king_mob;
double piece_cp;
double opp_min_att_cp;
double us_min_att_cp;
double see_cp;
double risk_cp;
int gives_check;
double score;
} MoveInfo;
static double score_move(const MoveInfo *m, unsigned int seed)
{
double s = 0.0;
if (m->gives_check)
{
double add = 200.0 + (40.0 * m->atk_opp_king) - (35.0 * m->opp_king_mob);
if (m->opp_king_mob <= 0.0)
{
add += 800.0;
}
s += add;
}
s += 1.5 * m->cap_cp;
if (m->cap_cp > 0.0)
{
double exch = m->cap_cp - m->piece_cp;
s += (m->piece_cp <= 120.0 ? 1.0 : 3.0) * exch;
if (m->piece_cp >= 850.0)
{
s -= 150.0;
}
}
s += 2.0 * m->prom_cp;
s += 1.2 * m->mat_cp;
s += 0.2 * m->see_cp;
s -= 1.0 * m->risk_cp;
double jitter = (double)(seed % 1000) / 1000000.0;
return s + jitter;
}
static unsigned int parse_seed(int *pargc, char ***pargv)
{
unsigned int seed = (unsigned int)time(NULL) ^ (unsigned int)getpid();
int argc = *pargc;
char **argv = *pargv;
for (int i = 1; i < argc; ++i)
{
if (strcmp(argv[i], "--seed") == 0 && i + 1 < argc)
{
seed = (unsigned int)strtoul(argv[i + 1], NULL, 10);
for (int j = i; j + 2 < argc; ++j)
{
argv[j] = argv[j + 2];
}
*pargc -= 2;
return seed;
}
}
return seed;
}
int main(int argc, char **argv)
{
if (argc <= 1)
{
fprintf(stderr, "usage: %s [--seed N] [--fen FEN] [--explain] [--analyze UCI] <moves...>\n",
argv[0]);
return 1;
}
unsigned int seed = parse_seed(&argc, &argv);
srand(seed);
int explain = 0;
const char *analyze_uci = NULL;
const char *fen = NULL;
for (int i = 1; i < argc; ++i)
{
if (strcmp(argv[i], "--explain") == 0)
{
explain = 1;
for (int j = i; j + 1 < argc; ++j)
{
argv[j] = argv[j + 1];
}
argc -= 1;
i -= 1;
}
else if (strcmp(argv[i], "--fen") == 0 && i + 1 < argc)
{
fen = argv[i + 1];
for (int j = i; j + 2 < argc; ++j)
{
argv[j] = argv[j + 2];
}
argc -= 2;
i -= 1;
}
else if (strcmp(argv[i], "--analyze") == 0 && i + 1 < argc)
{
analyze_uci = argv[i + 1];
for (int j = i; j + 2 < argc; ++j)
{
argv[j] = argv[j + 2];
}
argc -= 2;
i -= 1;
}
}
if (argc <= 1)
{
fprintf(stderr, "no moves provided\n");
return 1;
}
int n = argc - 1;
char **moves = &argv[1];
Board board;
int have_pos = 0;
if (fen)
{
if (!parse_fen(&board, fen))
{
fprintf(stderr, "invalid FEN\n");
return 1;
}
have_pos = 1;
}
int base_mat = 0;
if (have_pos)
{
base_mat = material_cp(&board);
}
MoveInfo *arr = (MoveInfo *)calloc((size_t)n, sizeof(MoveInfo));
if (!arr)
{
fprintf(stderr, "alloc failed\n");
return 1;
}
for (int i = 0; i < n; ++i)
{
strncpy(arr[i].uci, moves[i], sizeof(arr[i].uci) - 1);
arr[i].uci[sizeof(arr[i].uci) - 1] = '\0';
if (!have_pos)
{
arr[i].score = (double)rand() / (double)RAND_MAX;
continue;
}
Board after = board;
int cap = 0;
int pg = 0;
apply_move(&board, arr[i].uci, &after, &cap, &pg);
int mat_after = material_cp(&after);
int mat_raw = mat_after - base_mat;
int mat_signed = board.white_to_move ? mat_raw : -mat_raw;
arr[i].cap_cp = cap;
arr[i].prom_cp = pg;
arr[i].mat_cp = (double)mat_signed;
int from;
int to;
char pr = 0;
if (parse_uci(arr[i].uci, &from, &to, &pr))
{
char landed = after.squares[to];
arr[i].piece_cp = piece_value_cp(landed);
int opp_is_white = after.white_to_move;
int us_is_white = !after.white_to_move;
int opp_min = 0;
int us_min = 0;
// Use min of attackers by value (crude)
// We'll reuse piece values by scanning all pieces; simpler via count_attackers()
// surrogate Here we approximate with: if square attacked at all, assume min attacker is
// pawn (100)
if (sq_attacked_by(&after, to, opp_is_white))
{
opp_min = 100;
}
if (sq_attacked_by(&after, to, us_is_white))
{
us_min = 100;
}
arr[i].opp_min_att_cp = opp_min;
arr[i].us_min_att_cp = us_min;
arr[i].see_cp = (cap > 0) ? ((double)cap - (double)opp_min) : 0.0;
if (cap == 0 && opp_min > 0 && us_min == 0)
{
double risk = (double)opp_min;
if (risk > arr[i].piece_cp)
{
risk = arr[i].piece_cp;
}
arr[i].risk_cp = risk;
}
}
int opp_white = !board.white_to_move;
int opp_king = find_king(&after, opp_white);
int gives = 0;
if (opp_king >= 0)
{
gives = sq_attacked_by(&after, opp_king, !after.white_to_move);
int atk = count_attackers(&after, opp_king, !after.white_to_move);
int mob = 0;
int kf = file_of(opp_king);
int kr = rank_of(opp_king);
for (int df = -1; df <= 1; ++df)
{
for (int dr = -1; dr <= 1; ++dr)
{
if (df || dr)
{
int f = kf + df;
int r = kr + dr;
if (!on_board(f, r))
{
continue;
}
int idx = idx_from_fr(f, r);
char occ = after.squares[idx];
if (occ != '.' && (opp_white ? is_white(occ) : is_black(occ)))
{
continue;
}
if (!sq_attacked_by(&after, idx, !after.white_to_move))
{
mob++;
}
}
}
}
arr[i].atk_opp_king = atk;
arr[i].opp_king_mob = mob;
}
arr[i].gives_check = gives;
unsigned int local = seed ^ ((unsigned int)i * 2654435761U);
arr[i].score = score_move(&arr[i], local);
}
double best_score = -1e300;
int best_idx = -1;
for (int i = 0; i < n; ++i)
{
if (arr[i].score > best_score)
{
best_score = arr[i].score;
best_idx = i;
}
}
if (best_idx < 0)
{
free(arr);
fprintf(stderr, "no moves\n");
return 1;
}
if (!explain)
{
printf("%s\n", arr[best_idx].uci);
free(arr);
return 0;
}
printf("{\n");
printf(" \"seed\": %u,\n", seed);
if (have_pos)
{
printf(" \"fen\": \"%s\",\n", fen);
printf(" \"side_to_move\": \"%s\",\n", board.white_to_move ? "white" : "black");
printf(" \"base_material_cp\": %d,\n", base_mat);
}
printf(" \"n\": %d,\n", n);
printf(" \"moves\": [");
for (int i = 0; i < n; ++i)
{
printf("\"%s\"%s", arr[i].uci, (i + 1 < n ? ", " : ""));
}
printf("],\n");
printf(" \"scores\": [");
for (int i = 0; i < n; ++i)
{
printf("%.6f%s", arr[i].score, (i + 1 < n ? ", " : ""));
}
printf("],\n");
printf(" \"chosen_index\": %d,\n", best_idx);
printf(" \"chosen_move\": \"%s\"", arr[best_idx].uci);
if (analyze_uci)
{
int cand_idx = -1;
for (int i = 0; i < n; ++i)
{
if (strcmp(arr[i].uci, analyze_uci) == 0)
{
cand_idx = i;
break;
}
}
double cand_score = (cand_idx >= 0 ? arr[cand_idx].score : -1.0);
const char *cmp = "unknown";
if (cand_idx >= 0)
{
cmp = (cand_score > best_score ? "higher"
: (cand_score < best_score ? "lower" : "equal"));
}
printf(",\n \"analyze\": { \"candidate\": \"%s\", \"candidate_index\": %d, "
"\"candidate_score\": %.6f, \"compare_to_chosen\": \"%s\" }\n",
analyze_uci, cand_idx, cand_score, cmp);
}
else
{
printf("\n");
}
printf("}\n");
free(arr);
return 0;
}