70 lines
2.0 KiB
Python
70 lines
2.0 KiB
Python
from functools import partial
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import numpy as np
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import jax
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from jax import numpy as jnp, Array
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from jax import jit, vmap
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I_INT = np.iinfo(jnp.int32).max # infinite int
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EMPTY_NODE = np.full((1, 5), jnp.nan)
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EMPTY_CON = np.full((1, 4), jnp.nan)
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@jit
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def unflatten_connections(nodes: Array, cons: Array):
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"""
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transform the (C, 4) connections to (2, N, N)
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:param nodes: (N, 5)
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:param cons: (C, 4)
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:return:
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"""
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N = nodes.shape[0]
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node_keys = nodes[:, 0]
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i_keys, o_keys = cons[:, 0], cons[:, 1]
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i_idxs = vmap(key_to_indices, in_axes=(0, None))(i_keys, node_keys)
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o_idxs = vmap(key_to_indices, in_axes=(0, None))(o_keys, node_keys)
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res = jnp.full((2, N, N), jnp.nan)
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# Is interesting that jax use clip when attach data in array
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# however, it will do nothing set values in an array
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res = res.at[0, i_idxs, o_idxs].set(cons[:, 2])
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res = res.at[1, i_idxs, o_idxs].set(cons[:, 3])
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return res
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def key_to_indices(key, keys):
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return fetch_first(key == keys)
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@jit
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def fetch_first(mask, default=I_INT) -> Array:
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"""
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fetch the first True index
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:param mask: array of bool
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:param default: the default value if no element satisfying the condition
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:return: the index of the first element satisfying the condition. if no element satisfying the condition, return default value
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"""
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idx = jnp.argmax(mask)
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return jnp.where(mask[idx], idx, default)
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@jit
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def fetch_random(rand_key, mask, default=I_INT) -> Array:
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"""
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similar to fetch_first, but fetch a random True index
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"""
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true_cnt = jnp.sum(mask)
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cumsum = jnp.cumsum(mask)
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target = jax.random.randint(rand_key, shape=(), minval=1, maxval=true_cnt + 1)
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mask = jnp.where(true_cnt == 0, False, cumsum >= target)
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return fetch_first(mask, default)
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@partial(jit, static_argnames=['reverse'])
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def rank_elements(array, reverse=False):
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"""
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rank the element in the array.
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if reverse is True, the rank is from large to small.
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"""
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if reverse:
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array = -array
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return jnp.argsort(jnp.argsort(array)) |