from typing import Tuple import jax from jax import Array, numpy as jnp, vmap from config import NeatConfig from core import State, Gene, Genome from utils import check_cycles, fetch_random, fetch_first, I_INT, unflatten_conns def mutate(config: NeatConfig, gene: Gene, state: State, randkey, genome: Genome, new_node_key): """ Mutate a population of genomes """ k1, k2 = jax.random.split(randkey) genome = mutate_structure(config, gene, state, k1, genome, new_node_key) genome = mutate_values(gene, state, randkey, genome) return genome def mutate_structure(config: NeatConfig, gene: Gene, state: State, randkey, genome: Genome, new_node_key): def mutate_add_node(key_, genome_: Genome): i_key, o_key, idx = choice_connection_key(key_, genome_.conns) def nothing(): return genome_ def successful_add_node(): # disable the connection new_genome = genome_.update_conns(genome_.conns.at[idx, 2].set(False)) # add a new node new_genome = new_genome.add_node(new_node_key, gene.new_node_attrs(state)) # add two new connections new_genome = new_genome.add_conn(i_key, new_node_key, True, gene.new_conn_attrs(state)) new_genome = new_genome.add_conn(new_node_key, o_key, True, gene.new_conn_attrs(state)) return new_genome # if from_idx == I_INT, that means no connection exist, do nothing return jax.lax.cond(idx == I_INT, nothing, successful_add_node) def mutate_delete_node(key_, genome_: Genome): # TODO: Do we really need to delete a node? # randomly choose a node key, idx = choice_node_key(key_, genome_.nodes, state.input_idx, state.output_idx, allow_input_keys=False, allow_output_keys=False) def nothing(): return genome_ def successful_delete_node(): # delete the node new_genome = genome_.delete_node_by_pos(idx) # delete all connections new_conns = jnp.where(((new_genome.conns[:, 0] == key) | (new_genome.conns[:, 1] == key))[:, None], jnp.nan, new_genome.conns) return new_genome.update_conns(new_conns) return jax.lax.cond(idx == I_INT, nothing, successful_delete_node) def mutate_add_conn(key_, genome_: Genome): # randomly choose two nodes k1_, k2_ = jax.random.split(key_, num=2) i_key, from_idx = choice_node_key(k1_, genome_.nodes, state.input_idx, state.output_idx, allow_input_keys=True, allow_output_keys=True) o_key, to_idx = choice_node_key(k2_, genome_.nodes, state.input_idx, state.output_idx, allow_input_keys=False, allow_output_keys=True) conn_pos = fetch_first((genome_.conns[:, 0] == i_key) & (genome_.conns[:, 1] == o_key)) def nothing(): return genome_ def successful(): return genome_.add_conn(i_key, o_key, True, gene.new_conn_attrs(state)) def already_exist(): return genome_.update_conns(genome_.conns.at[conn_pos, 2].set(True)) is_already_exist = conn_pos != I_INT if config.network_type == 'feedforward': u_cons = unflatten_conns(genome_.nodes, genome_.conns) cons_exist = jnp.where(~jnp.isnan(u_cons[0, :, :]), True, False) is_cycle = check_cycles(genome_.nodes, cons_exist, from_idx, to_idx) choice = jnp.where(is_already_exist, 0, jnp.where(is_cycle, 1, 2)) return jax.lax.switch(choice, [already_exist, nothing, successful]) elif config.network_type == 'recurrent': return jax.lax.cond(is_already_exist, already_exist, successful) else: raise ValueError(f"Invalid network type: {config.network_type}") def mutate_delete_conn(key_, genome_: Genome): # randomly choose a connection i_key, o_key, idx = choice_connection_key(key_, genome_.conns) def nothing(): return genome_ def successfully_delete_connection(): return genome_.delete_conn_by_pos(idx) return jax.lax.cond(idx == I_INT, nothing, successfully_delete_connection) k1, k2, k3, k4 = jax.random.split(randkey, num=4) r1, r2, r3, r4 = jax.random.uniform(k1, shape=(4,)) def no(k, g): return g genome = jax.lax.cond(r1 < config.node_add, mutate_add_node, no, k1, genome) genome = jax.lax.cond(r2 < config.node_delete, mutate_delete_node, no, k2, genome) genome = jax.lax.cond(r3 < config.conn_add, mutate_add_conn, no, k3, genome) genome = jax.lax.cond(r4 < config.conn_delete, mutate_delete_conn, no, k4, genome) return genome def mutate_values(gene: Gene, state: State, randkey, genome: Genome): k1, k2 = jax.random.split(randkey, num=2) nodes_keys = jax.random.split(k1, num=genome.nodes.shape[0]) conns_keys = jax.random.split(k2, num=genome.conns.shape[0]) nodes_attrs, conns_attrs = genome.nodes[:, 1:], genome.conns[:, 3:] new_nodes_attrs = vmap(gene.mutate_node, in_axes=(None, 0, 0))(state, nodes_keys, nodes_attrs) new_conns_attrs = vmap(gene.mutate_conn, in_axes=(None, 0, 0))(state, conns_keys, conns_attrs) # nan nodes not changed new_nodes_attrs = jnp.where(jnp.isnan(nodes_attrs), jnp.nan, new_nodes_attrs) new_conns_attrs = jnp.where(jnp.isnan(conns_attrs), jnp.nan, new_conns_attrs) new_nodes = genome.nodes.at[:, 1:].set(new_nodes_attrs) new_conns = genome.conns.at[:, 3:].set(new_conns_attrs) return genome.update(new_nodes, new_conns) def choice_node_key(rand_key: Array, nodes: Array, input_keys: Array, output_keys: Array, allow_input_keys: bool = False, allow_output_keys: bool = False) -> Tuple[Array, Array]: """ Randomly choose a node key from the given nodes. It guarantees that the chosen node not be the input or output node. :param rand_key: :param nodes: :param input_keys: :param output_keys: :param allow_input_keys: :param allow_output_keys: :return: return its key and position(idx) """ node_keys = nodes[:, 0] mask = ~jnp.isnan(node_keys) if not allow_input_keys: mask = jnp.logical_and(mask, ~jnp.isin(node_keys, input_keys)) if not allow_output_keys: mask = jnp.logical_and(mask, ~jnp.isin(node_keys, output_keys)) idx = fetch_random(rand_key, mask) key = jnp.where(idx != I_INT, nodes[idx, 0], jnp.nan) return key, idx def choice_connection_key(rand_key: Array, conns: Array): """ Randomly choose a connection key from the given connections. :return: i_key, o_key, idx """ idx = fetch_random(rand_key, ~jnp.isnan(conns[:, 0])) i_key = jnp.where(idx != I_INT, conns[idx, 0], jnp.nan) o_key = jnp.where(idx != I_INT, conns[idx, 1], jnp.nan) return i_key, o_key, idx