bug about go game

[Nightbringers]

[300, 60, 288, 72, 97, 67, 63, 81, 40, 59, 41, 61, 58, 42, 77, 102, 84, 83, 64, 65, 111, 46, 54, 73, 53, 71, 74, 263, 282, 262, 298, 52, 93, 315, 296, 295, 277, 316, 317, 311, 205, 207, 206, 260, 279, 188, 226, 245, 225, 167, 227, 283, 302, 240, 222, 280, 284, 264, 276, 320, 301, 299, 319, 318, 337, 336, 338, 294, 147, 335, 238, 221, 200, 183, 166, 163, 127, 255, 217, 249, 160, 125, 310, 291, 309, 330, 268, 250, 290, 272, 215, 197, 216, 271, 248, 229, 267, 180, 211, 219, 218, 256, 257, 220, 237, 179, 196, 109, 148, 230, 159, 326, 327, 307, 289, 185, 186, 157, 181, 161, 162, 142, 199, 203, 143, 126, 210, 209, 124, 122, 212, 155, 172, 153, 134, 135, 152, 173, 154, 305, 324, 153, 190, 228, 154, 168, 149, 153, 275, 274, 154, 23, 116, 153, 204, 184, 154, 136, 108, 88, 89, 69, 232, 269, 306, 325, 287, 323, 343, 344, 242, 346, 347, 261, 285, 329, 328, 178, 33, 32, 34, 13, 86, 87, 85, 342, 66, 47, 48, 68, 29, 45, 324, 247, 304, 343, 175, 270, 286, 348, 156, 137, 138, 119, 158, 139, 176, 266, 345, 138, 177, 21, 39, 22, 99, 100, 174, 153, 123, 141, 154, 346, 324, 153, 345, 305]. this is full action, when move the last move, game terminated strangely

[sotetsuk]

Thank you sharing! I'll investigate tomorrow.

[sotetsuk]

It looks like the last action is illegal as it's PSK. Last state states[-1] and states[-7] are the same. I suppose it should have been omitted from legal action but it's legal now. I'll investigate it further.

states[-1]

states[-2]

states[-3]

states[-4]

states[-5]

states[-6]

states[-7]

states[-8]

code:

import jax
import jax.numpy as jnp
import pgx

actions = [300, 60, 288, 72, 97, 67, 63, 81, 40, 59, 41, 61, 58, 42, 77, 102, 84, 83, 64, 65, 111, 46, 54, 73, 53, 71, 74, 263, 282, 262, 298, 52, 93, 315, 296, 295, 277, 316, 317, 311, 205, 207, 206, 260, 279, 188, 226, 245, 225, 167, 227, 283, 302, 240, 222, 280, 284, 264, 276, 320, 301, 299, 319, 318, 337, 336, 338, 294, 147, 335, 238, 221, 200, 183, 166, 163, 127, 255, 217, 249, 160, 125, 310, 291, 309, 330, 268, 250, 290, 272, 215, 197, 216, 271, 248, 229, 267, 180, 211, 219, 218, 256, 257, 220, 237, 179, 196, 109, 148, 230, 159, 326, 327, 307, 289, 185, 186, 157, 181, 161, 162, 142, 199, 203, 143, 126, 210, 209, 124, 122, 212, 155, 172, 153, 134, 135, 152, 173, 154, 305, 324, 153, 190, 228, 154, 168, 149, 153, 275, 274, 154, 23, 116, 153, 204, 184, 154, 136, 108, 88, 89, 69, 232, 269, 306, 325, 287, 323, 343, 344, 242, 346, 347, 261, 285, 329, 328, 178, 33, 32, 34, 13, 86, 87, 85, 342, 66, 47, 48, 68, 29, 45, 324, 247, 304, 343, 175, 270, 286, 348, 156, 137, 138, 119, 158, 139, 176, 266, 345, 138, 177, 21, 39, 22, 99, 100, 174, 153, 123, 141, 154, 346, 324, 153, 345, 305]

env = pgx.make("go_19x19")
key = jax.random.PRNGKey(0)
init_fn = jax.jit(env.init)
step_fn = jax.jit(env.step)

states = []

state = init_fn(key)
states.append(state)
for a in actions:
    print(a, f"legal? {state.legal_action_mask[a]}")
    state = step_fn(state, a)
    print(a, f"terminated? {state.terminated}")
    print(a, f"psk? {state._x.is_psk}")
    states.append(state)

for i in range(1, 9):
    pgx.save_svg(states[-i], f"last_state_m{i}.svg")
pgx.save_svg_animation(states, "states.svg")

outputs:

...
153 psk? False
345 legal? True
345 terminated? False
345 psk? False
305 legal? True
305 terminated? True
305 psk? True

[sotetsuk]

After some investigation, I concluded that this is not the bug. This game ends due to PSK. However, it's allowed in the legal action and the agent is expected to learn it. This is our specification. This is described in our document: https://sotets.uk/pgx/go/

Also, I suppose OpenSpiel also has the similar behavior. I guess the game would end in tie in OpenSpiel.

Anyway, thank you four your report!

[Nightbringers]

Does the presence of dead stones on the board affect the win or lose in go game？

[sotetsuk]

It follows the Tromp Taylor rule https://tromp.github.io/go.html

[Nightbringers]

it says : A player's score is the number of points of her color, plus the number of empty points that reach only her color. So if dead stones not cleaned, it will counted into score, and affect the result?

[Nightbringers]

PSK

finanlly understand，thanks. This is the first time that i know this rule.