syzygy / fathom

[flok]

What could be wrong if fathom/syzygy only returns 0-results? e.g. with TB_GET_WDL only returning 0? It has the 6-men table-base.

I tried 4k3/8/8/8/8/8/1B6/1B2K3 w - - 0 1 and also 4k3/8/8/8/8/8/1B6/1B2K3 b - - 0 1

Code: Select all

struct pos
{
        uint64_t white;
        uint64_t black;
        uint64_t kings;
        uint64_t queens;
        uint64_t rooks;
        uint64_t bishops;
        uint64_t knights;
        uint64_t pawns;
        uint8_t castling;
        uint8_t rule50;
        uint8_t ep;
        bool turn;
};

std::optional<libchess::Move> get_first_move(struct pos & pos, unsigned *results, unsigned wdl)
{
        for(unsigned i = 0; results[i] != TB_RESULT_FAILED; i++) {
                printf("hier %u %u=%u\n", i, TB_GET_WDL(results[i]), wdl);
                if (TB_GET_WDL(results[i]) == wdl) {
                        unsigned move     = results[i];

                        unsigned from     = TB_GET_FROM(move);
                        unsigned to       = TB_GET_TO(move);
                        unsigned promotes = TB_GET_PROMOTES(move);

                        char to_type = 0x00;

                        switch (promotes)
                        {
                                case TB_PROMOTES_QUEEN:
                                        to_type = 'q'; break;
                                case TB_PROMOTES_ROOK:
                                        to_type = 'r'; break;
                                case TB_PROMOTES_BISHOP:
                                        to_type = 'b'; break;
                                case TB_PROMOTES_KNIGHT:
                                        to_type = 'n'; break;
                        }

                        std::string move_str = myformat("%c%c%c%c%c", from & 7, from >> 3, to & 7, to >> 3, to_type);

                        printf("found %s\n", move_str.c_str());

                        return libchess::Move::from(move_str);
                }
        }

        return {};
}


std::optional<libchess::Move> probe_fathom(libchess::Position & lpos)
{
        struct pos pos;
        pos.turn == lpos.side_to_move() == libchess::constants::WHITE;
        pos.white = lpos.color_bb(libchess::constants::WHITE);
        pos.black = lpos.color_bb(libchess::constants::BLACK);
        pos.kings = lpos.piece_type_bb(libchess::constants::KING);
        pos.queens = lpos.piece_type_bb(libchess::constants::QUEEN);
        pos.rooks = lpos.piece_type_bb(libchess::constants::ROOK);
        pos.bishops = lpos.piece_type_bb(libchess::constants::BISHOP);
        pos.knights = lpos.piece_type_bb(libchess::constants::KNIGHT);
        pos.pawns = lpos.piece_type_bb(libchess::constants::PAWN);
        //uint8_t castling;
        pos.castling = 0; // FIXME
        pos.rule50 = lpos.fullmoves();
        std::optional<libchess::Square> ep = lpos.enpassant_square();
        pos.ep = ep.has_value() ? ep.value() : 0;

        unsigned results[TB_MAX_MOVES];
        unsigned res = tb_probe_root(pos.white, pos.black, pos.kings, pos.queens, pos.rooks, pos.bishops, pos.knights, pos.pawns, pos.rule50, pos.castling, pos.ep, pos.turn, results);

        if (res == TB_RESULT_FAILED) {
                printf("# TB_RESULT_FAILED\n");
                return {};
        }

        //printf("# %d\n", TB_GET_WDL(res));

        std::optional<libchess::Move> m;

        m = get_first_move(pos, results, TB_WIN);
        if (m.has_value())
                return m;

        m = get_first_move(pos, results, TB_CURSED_WIN);
        if (m.has_value())
                return m;

        m = get_first_move(pos, results, TB_DRAW);
        if (m.has_value())
                return m;

        m = get_first_move(pos, results, TB_BLESSED_LOSS);
        if (m.has_value())
                return m;

        return {};
}

[flok]

Please ignore this bug, I fixed that already

Code: Select all

        pos.turn == lpos.side_to_move() == libchess::constants::WHITE;

The only wdl==0 problem disappeared, now every query returns TB_RESULT_FAILED

[flok]

Ok I verified that at least the white and the bishop bitboard are the same (when comparing the fathom commandline tool and what micah produces).
So I'm still puzzled why it doesn't work!

[flok]

Ok I verified that at least the white and the bishop bitboard are the same (when comparing the fathom commandline tool and what micah produces).
So I'm still puzzled why it doesn't work!

In fact: all bitboards and other values (ep, castling, etc) are the same. So that's not the problem.

[flok]

Code: Select all

                        char to_type = 0x00;
...
                        std::string move_str = myformat("%c%c%c%c%c", from & 7, from >> 3, to & 7, to >> 3, to_type);

This is a problem.

[jdart]

Which Fathom are you using? Is it https://github.com/jdart1/Fathom?

If the command-line tool works on your position, then you have to be passing something different into the API for it to not work for you. You do have to call tb_init first.

Btw. the newer and now preferred root level probing API call is tb_probe_root_dtz, or as a fallback, tb_probe_root_wdl.

--Jon

[flok]

Which Fathom are you using? Is it https://github.com/jdart1/Fathom?

If the command-line tool works on your position, then you have to be passing something different into the API for it to not work for you. You do have to call tb_init first.

Btw. the newer and now preferred root level probing API call is tb_probe_root_dtz, or as a fallback, tb_probe_root_wdl.

--Jon

Got it to work!

Thanks

Next step: not only at the root but in tree check as well.