31 lines
791 B
Python
Executable file
31 lines
791 B
Python
Executable file
#!/usr/bin/env python3
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"""Pre-compute knight ray bitboards for each square."""
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TEMPLATE = """\
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/// Pre-computed knight rays.
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pub const KNIGHT_RAYS: [Bitboard; 64] = [
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{}
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];
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"""
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DIRS = [(1, 2), (2, 1), (2, -1), (1, -2), (-1, -2), (-2, -1), (-2, 1), (-1, 2)]
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def bit_pos(square):
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return 1 << square
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def get_rays():
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rays = []
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for f in range(8):
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for r in range(8):
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bitboard = 0
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for dir_f, dir_r in DIRS:
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ray_f = f + dir_f
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ray_r = r + dir_r
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if ray_f < 0 or ray_f > 7 or ray_r < 0 or ray_r > 7:
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continue
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bitboard |= bit_pos(ray_f * 8 + ray_r)
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rays.append(" 0b{:064b},".format(bitboard))
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return rays
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print(TEMPLATE.format("\n".join(get_rays())))
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