Upload 2 files
Browse files- evolutionary_turing.py +371 -0
- evolutionary_turing_docs.py +955 -0
evolutionary_turing.py
ADDED
|
@@ -0,0 +1,371 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
############################################################################################################################################
|
| 2 |
+
#|| - - - |8.19.2025| - - - || Evolutionary Turing Machine || - - - | 1990two | - - -||#
|
| 3 |
+
############################################################################################################################################
|
| 4 |
+
|
| 5 |
+
from __future__ import annotations
|
| 6 |
+
from dataclasses import dataclass
|
| 7 |
+
from typing import Dict, List, Optional, Tuple, Union
|
| 8 |
+
import math
|
| 9 |
+
import torch
|
| 10 |
+
import torch.nn as nn
|
| 11 |
+
import torch.nn.functional as F
|
| 12 |
+
from copy import deepcopy
|
| 13 |
+
|
| 14 |
+
|
| 15 |
+
@dataclass
|
| 16 |
+
class NTMConfig:
|
| 17 |
+
input_dim: int
|
| 18 |
+
output_dim: int
|
| 19 |
+
controller_dim: int = 128
|
| 20 |
+
controller_layers: int = 1
|
| 21 |
+
memory_slots: int = 128
|
| 22 |
+
memory_dim: int = 32
|
| 23 |
+
heads_read: int = 1
|
| 24 |
+
heads_write: int = 1
|
| 25 |
+
init_std: float = 0.1
|
| 26 |
+
|
| 27 |
+
############################################################################################################################################
|
| 28 |
+
#################################################### - - - Neural Turing Machine - - - ###############################################
|
| 29 |
+
|
| 30 |
+
class NeuralTuringMachine(nn.Module):
|
| 31 |
+
def __init__(self, cfg: NTMConfig):
|
| 32 |
+
super().__init__()
|
| 33 |
+
self.cfg = cfg
|
| 34 |
+
R, W, Dm = cfg.heads_read, cfg.heads_write, cfg.memory_dim
|
| 35 |
+
|
| 36 |
+
ctrl_in = cfg.input_dim + R * Dm
|
| 37 |
+
self.controller = nn.LSTMCell(ctrl_in, cfg.controller_dim)
|
| 38 |
+
|
| 39 |
+
iface_read = R * (Dm + 1) # key + strength
|
| 40 |
+
iface_write = W * (Dm + 1 + Dm + Dm) # key + strength + erase + add
|
| 41 |
+
self.interface = nn.Linear(cfg.controller_dim, iface_read + iface_write)
|
| 42 |
+
self.output = nn.Linear(cfg.controller_dim + R * Dm, cfg.output_dim)
|
| 43 |
+
|
| 44 |
+
self.reset_parameters()
|
| 45 |
+
|
| 46 |
+
def reset_parameters(self):
|
| 47 |
+
for m in self.modules():
|
| 48 |
+
if isinstance(m, nn.Linear):
|
| 49 |
+
nn.init.xavier_uniform_(m.weight)
|
| 50 |
+
nn.init.zeros_(m.bias)
|
| 51 |
+
if isinstance(m, nn.LSTMCell):
|
| 52 |
+
nn.init.xavier_uniform_(m.weight_ih)
|
| 53 |
+
nn.init.orthogonal_(m.weight_hh)
|
| 54 |
+
nn.init.zeros_(m.bias_ih)
|
| 55 |
+
nn.init.zeros_(m.bias_hh)
|
| 56 |
+
hs = m.bias_ih.shape[0] // 4
|
| 57 |
+
m.bias_ih.data[hs:2*hs].fill_(1.0) # forget gate
|
| 58 |
+
m.bias_hh.data[hs:2*hs].fill_(1.0)
|
| 59 |
+
|
| 60 |
+
|
| 61 |
+
def initial_state(self, batch_size: int, device=None):
|
| 62 |
+
cfg = self.cfg
|
| 63 |
+
device = device or next(self.parameters()).device
|
| 64 |
+
|
| 65 |
+
M = torch.zeros(batch_size, cfg.memory_slots, cfg.memory_dim, device=device)
|
| 66 |
+
if cfg.init_std > 0:
|
| 67 |
+
M.normal_(0.0, cfg.init_std)
|
| 68 |
+
|
| 69 |
+
w_r = torch.ones(batch_size, cfg.heads_read, cfg.memory_slots, device=device) / cfg.memory_slots
|
| 70 |
+
w_w = torch.ones(batch_size, cfg.heads_write, cfg.memory_slots, device=device) / cfg.memory_slots
|
| 71 |
+
r = torch.zeros(batch_size, cfg.heads_read, cfg.memory_dim, device=device)
|
| 72 |
+
h = torch.zeros(batch_size, cfg.controller_dim, device=device)
|
| 73 |
+
c = torch.zeros(batch_size, cfg.controller_dim, device=device)
|
| 74 |
+
|
| 75 |
+
return {'M': M, 'w_r': w_r, 'w_w': w_w, 'r': r, 'h': h, 'c': c}
|
| 76 |
+
|
| 77 |
+
def step(self, x: torch.Tensor, state: Dict[str, torch.Tensor]):
|
| 78 |
+
cfg = self.cfg
|
| 79 |
+
B = x.shape[0]
|
| 80 |
+
|
| 81 |
+
ctrl_in = torch.cat([x, state['r'].view(B, -1)], dim=-1)
|
| 82 |
+
h, c = self.controller(ctrl_in, (state['h'], state['c']))
|
| 83 |
+
iface = self.interface(h)
|
| 84 |
+
R, W, Dm = cfg.heads_read, cfg.heads_write, cfg.memory_dim
|
| 85 |
+
|
| 86 |
+
offset = 0
|
| 87 |
+
k_r = iface[:, offset:offset + R * Dm].view(B, R, Dm)
|
| 88 |
+
offset += R * Dm
|
| 89 |
+
beta_r = F.softplus(iface[:, offset:offset + R])
|
| 90 |
+
offset += R
|
| 91 |
+
|
| 92 |
+
k_w = iface[:, offset:offset + W * Dm].view(B, W, Dm)
|
| 93 |
+
offset += W * Dm
|
| 94 |
+
beta_w = F.softplus(iface[:, offset:offset + W])
|
| 95 |
+
offset += W
|
| 96 |
+
erase = torch.sigmoid(iface[:, offset:offset + W * Dm]).view(B, W, Dm)
|
| 97 |
+
offset += W * Dm
|
| 98 |
+
add = torch.tanh(iface[:, offset:offset + W * Dm]).view(B, W, Dm)
|
| 99 |
+
|
| 100 |
+
def address(M, k, beta, prev_weight=None):
|
| 101 |
+
M_norm = torch.norm(M, dim=-1, keepdim=True).clamp_min(1e-8)
|
| 102 |
+
k_norm = torch.norm(k, dim=-1, keepdim=True).clamp_min(1e-8)
|
| 103 |
+
cos_sim = torch.sum(M.unsqueeze(1) * k.unsqueeze(2), dim=-1) / (
|
| 104 |
+
M_norm.squeeze(-1).unsqueeze(1) * k_norm.squeeze(-1).unsqueeze(-1)
|
| 105 |
+
)
|
| 106 |
+
content_logits = beta.unsqueeze(-1) * cos_sim
|
| 107 |
+
if prev_weight is not None:
|
| 108 |
+
content_logits = content_logits + 0.02 * prev_weight
|
| 109 |
+
return F.softmax(content_logits, dim=-1)
|
| 110 |
+
|
| 111 |
+
|
| 112 |
+
w_r = address(state['M'], k_r, beta_r, prev_weight=state.get('w_r'))
|
| 113 |
+
w_w = address(state['M'], k_w, beta_w, prev_weight=state.get('w_w'))
|
| 114 |
+
r = torch.sum(w_r.unsqueeze(-1) * state['M'].unsqueeze(1), dim=2)
|
| 115 |
+
|
| 116 |
+
M = state['M']
|
| 117 |
+
if W > 0:
|
| 118 |
+
erase_term = torch.prod(1 - w_w.unsqueeze(-1) * erase.unsqueeze(2), dim=1)
|
| 119 |
+
M = M * erase_term
|
| 120 |
+
add_term = torch.sum(w_w.unsqueeze(-1) * add.unsqueeze(2), dim=1)
|
| 121 |
+
M = M + add_term
|
| 122 |
+
|
| 123 |
+
y = self.output(torch.cat([h, r.view(B, -1)], dim=-1))
|
| 124 |
+
|
| 125 |
+
new_state = {'M': M, 'w_r': w_r, 'w_w': w_w, 'r': r, 'h': h, 'c': c}
|
| 126 |
+
return y, new_state
|
| 127 |
+
|
| 128 |
+
def forward(self, x: torch.Tensor, state=None):
|
| 129 |
+
if x.dim() == 2:
|
| 130 |
+
if state is None:
|
| 131 |
+
state = self.initial_state(x.shape[0], x.device)
|
| 132 |
+
return self.step(x, state)
|
| 133 |
+
|
| 134 |
+
B, T, _ = x.shape
|
| 135 |
+
if state is None:
|
| 136 |
+
state = self.initial_state(B, x.device)
|
| 137 |
+
|
| 138 |
+
outputs = []
|
| 139 |
+
for t in range(T):
|
| 140 |
+
y, state = self.step(x[:, t], state)
|
| 141 |
+
outputs.append(y)
|
| 142 |
+
|
| 143 |
+
return torch.stack(outputs, dim=1), state
|
| 144 |
+
|
| 145 |
+
@dataclass
|
| 146 |
+
class EvolutionaryTuringConfig:
|
| 147 |
+
population_size: int = 100
|
| 148 |
+
mutation_rate: float = 0.1
|
| 149 |
+
architecture_mutation_rate: float = 0.05
|
| 150 |
+
elite_ratio: float = 0.2
|
| 151 |
+
max_generations: int = 200
|
| 152 |
+
input_dim: int = 8
|
| 153 |
+
output_dim: int = 8
|
| 154 |
+
device: str = 'cpu'
|
| 155 |
+
seed: Optional[int] = None
|
| 156 |
+
|
| 157 |
+
############################################################################################################################################
|
| 158 |
+
################################################# - - - Fitness Evaluation - - - #####################################################
|
| 159 |
+
|
| 160 |
+
class FitnessEvaluator:
|
| 161 |
+
def __init__(self, device: str = 'cpu'):
|
| 162 |
+
self.device = device
|
| 163 |
+
|
| 164 |
+
def copy_task(self, ntm: NeuralTuringMachine, seq_len: int = 8, batch_size: int = 16) -> float:
|
| 165 |
+
with torch.no_grad():
|
| 166 |
+
x = torch.randint(0, 2, (batch_size, seq_len, ntm.cfg.input_dim),
|
| 167 |
+
device=self.device, dtype=torch.float32)
|
| 168 |
+
|
| 169 |
+
delimiter = torch.zeros(batch_size, 1, ntm.cfg.input_dim, device=self.device)
|
| 170 |
+
delimiter[:, :, -1] = 1
|
| 171 |
+
|
| 172 |
+
input_seq = torch.cat([x, delimiter], dim=1)
|
| 173 |
+
try:
|
| 174 |
+
output, _ = ntm(input_seq)
|
| 175 |
+
T = seq_len
|
| 176 |
+
D = ntm.cfg.output_dim
|
| 177 |
+
pred = output[:, -T:, :D]
|
| 178 |
+
d = min(ntm.cfg.input_dim, D)
|
| 179 |
+
loss = F.mse_loss(pred[..., :d], x[..., :d])
|
| 180 |
+
accuracy = 1.0 / (1.0 + loss.item())
|
| 181 |
+
return accuracy
|
| 182 |
+
except:
|
| 183 |
+
return 0.0
|
| 184 |
+
|
| 185 |
+
|
| 186 |
+
def associative_recall(self, ntm: NeuralTuringMachine, num_pairs: int = 4) -> float:
|
| 187 |
+
with torch.no_grad():
|
| 188 |
+
batch_size = 8
|
| 189 |
+
dim = ntm.cfg.input_dim
|
| 190 |
+
keys = torch.randn(batch_size, num_pairs, dim // 2, device=self.device)
|
| 191 |
+
values = torch.randn(batch_size, num_pairs, dim // 2, device=self.device)
|
| 192 |
+
pairs = torch.cat([keys, values], dim=-1)
|
| 193 |
+
|
| 194 |
+
test_keys = torch.cat([keys, torch.zeros_like(values)], dim=-1)
|
| 195 |
+
expected_values = torch.cat([torch.zeros_like(keys), values], dim=-1)
|
| 196 |
+
|
| 197 |
+
input_seq = torch.cat([pairs, test_keys], dim=1) # (B, 2P, dim)
|
| 198 |
+
target_seq = torch.cat([torch.zeros_like(pairs), expected_values], dim=1)
|
| 199 |
+
|
| 200 |
+
try:
|
| 201 |
+
output, _ = ntm(input_seq) # (B, 2P, out_dim)
|
| 202 |
+
D = ntm.cfg.output_dim
|
| 203 |
+
d = min(dim, D)
|
| 204 |
+
loss = F.mse_loss(output[:, num_pairs:, :d], target_seq[:, num_pairs:, :d])
|
| 205 |
+
accuracy = 1.0 / (1.0 + loss.item())
|
| 206 |
+
return accuracy
|
| 207 |
+
except:
|
| 208 |
+
return 0.0
|
| 209 |
+
|
| 210 |
+
|
| 211 |
+
def evaluate_fitness(self, ntm: NeuralTuringMachine) -> Dict[str, float]:
|
| 212 |
+
copy_score = self.copy_task(ntm)
|
| 213 |
+
recall_score = self.associative_recall(ntm)
|
| 214 |
+
|
| 215 |
+
param_count = sum(p.numel() for p in ntm.parameters())
|
| 216 |
+
efficiency = 1.0 / (1.0 + param_count / 100000)
|
| 217 |
+
|
| 218 |
+
composite_score = 0.5 * copy_score + 0.3 * recall_score + 0.2 * efficiency
|
| 219 |
+
|
| 220 |
+
return {
|
| 221 |
+
'copy': copy_score,
|
| 222 |
+
'recall': recall_score,
|
| 223 |
+
'efficiency': efficiency,
|
| 224 |
+
'composite': composite_score
|
| 225 |
+
}
|
| 226 |
+
|
| 227 |
+
############################################################################################################################################
|
| 228 |
+
############################################## - - - Evolutionary Turing Machine - - - ###############################################
|
| 229 |
+
|
| 230 |
+
class EvolutionaryTuringMachine:
|
| 231 |
+
def __init__(self, cfg: EvolutionaryTuringConfig):
|
| 232 |
+
self.cfg = cfg
|
| 233 |
+
self.evaluator = FitnessEvaluator(cfg.device)
|
| 234 |
+
self.generation = 0
|
| 235 |
+
self.best_fitness = 0.0
|
| 236 |
+
self.population = []
|
| 237 |
+
|
| 238 |
+
if cfg.seed is not None:
|
| 239 |
+
torch.manual_seed(cfg.seed)
|
| 240 |
+
|
| 241 |
+
def create_random_config(self) -> NTMConfig:
|
| 242 |
+
return NTMConfig(
|
| 243 |
+
input_dim=self.cfg.input_dim,
|
| 244 |
+
output_dim=self.cfg.output_dim,
|
| 245 |
+
controller_dim=torch.randint(64, 256, (1,)).item(),
|
| 246 |
+
controller_layers=torch.randint(1, 3, (1,)).item(),
|
| 247 |
+
memory_slots=torch.randint(32, 256, (1,)).item(),
|
| 248 |
+
memory_dim=torch.randint(16, 64, (1,)).item(),
|
| 249 |
+
heads_read=torch.randint(1, 4, (1,)).item(),
|
| 250 |
+
heads_write=torch.randint(1, 3, (1,)).item(),
|
| 251 |
+
init_std=0.1
|
| 252 |
+
)
|
| 253 |
+
|
| 254 |
+
def mutate_architecture(self, cfg: NTMConfig) -> NTMConfig:
|
| 255 |
+
new_cfg = deepcopy(cfg)
|
| 256 |
+
|
| 257 |
+
if torch.rand(1) < self.cfg.architecture_mutation_rate:
|
| 258 |
+
new_cfg.controller_dim = max(32, new_cfg.controller_dim + torch.randint(-32, 33, (1,)).item())
|
| 259 |
+
|
| 260 |
+
if torch.rand(1) < self.cfg.architecture_mutation_rate:
|
| 261 |
+
new_cfg.memory_slots = max(16, new_cfg.memory_slots + torch.randint(-16, 17, (1,)).item())
|
| 262 |
+
|
| 263 |
+
if torch.rand(1) < self.cfg.architecture_mutation_rate:
|
| 264 |
+
new_cfg.memory_dim = max(8, new_cfg.memory_dim + torch.randint(-8, 9, (1,)).item())
|
| 265 |
+
|
| 266 |
+
if torch.rand(1) < self.cfg.architecture_mutation_rate:
|
| 267 |
+
new_cfg.heads_read = max(1, min(4, new_cfg.heads_read + torch.randint(-1, 2, (1,)).item()))
|
| 268 |
+
|
| 269 |
+
if torch.rand(1) < self.cfg.architecture_mutation_rate:
|
| 270 |
+
new_cfg.heads_write = max(1, min(3, new_cfg.heads_write + torch.randint(-1, 2, (1,)).item()))
|
| 271 |
+
|
| 272 |
+
return new_cfg
|
| 273 |
+
|
| 274 |
+
def mutate_parameters(self, ntm: NeuralTuringMachine) -> NeuralTuringMachine:
|
| 275 |
+
new_ntm = NeuralTuringMachine(ntm.cfg).to(self.cfg.device)
|
| 276 |
+
new_ntm.load_state_dict(deepcopy(ntm.state_dict()))
|
| 277 |
+
with torch.no_grad():
|
| 278 |
+
for p in new_ntm.parameters():
|
| 279 |
+
mask = (torch.rand_like(p) < self.cfg.mutation_rate)
|
| 280 |
+
p.add_(torch.randn_like(p) * 0.01 * mask)
|
| 281 |
+
return new_ntm
|
| 282 |
+
|
| 283 |
+
|
| 284 |
+
def crossover(self, parent1: NeuralTuringMachine, parent2: NeuralTuringMachine) -> NeuralTuringMachine:
|
| 285 |
+
cfg1, cfg2 = parent1.cfg, parent2.cfg
|
| 286 |
+
|
| 287 |
+
new_cfg = NTMConfig(
|
| 288 |
+
input_dim=self.cfg.input_dim,
|
| 289 |
+
output_dim=self.cfg.output_dim,
|
| 290 |
+
controller_dim=cfg1.controller_dim if torch.rand(1) < 0.5 else cfg2.controller_dim,
|
| 291 |
+
memory_slots=cfg1.memory_slots if torch.rand(1) < 0.5 else cfg2.memory_slots,
|
| 292 |
+
memory_dim=cfg1.memory_dim if torch.rand(1) < 0.5 else cfg2.memory_dim,
|
| 293 |
+
heads_read=cfg1.heads_read if torch.rand(1) < 0.5 else cfg2.heads_read,
|
| 294 |
+
heads_write=cfg1.heads_write if torch.rand(1) < 0.5 else cfg2.heads_write,
|
| 295 |
+
init_std=0.1
|
| 296 |
+
)
|
| 297 |
+
|
| 298 |
+
child = NeuralTuringMachine(new_cfg).to(self.cfg.device)
|
| 299 |
+
return child
|
| 300 |
+
|
| 301 |
+
def initialize_population(self):
|
| 302 |
+
self.population = []
|
| 303 |
+
for _ in range(self.cfg.population_size):
|
| 304 |
+
cfg = self.create_random_config()
|
| 305 |
+
ntm = NeuralTuringMachine(cfg).to(self.cfg.device)
|
| 306 |
+
self.population.append(ntm)
|
| 307 |
+
|
| 308 |
+
def evolve_generation(self) -> Dict[str, float]:
|
| 309 |
+
fitness_scores = []
|
| 310 |
+
for ntm in self.population:
|
| 311 |
+
fitness = self.evaluator.evaluate_fitness(ntm)
|
| 312 |
+
fitness_scores.append(fitness['composite'])
|
| 313 |
+
|
| 314 |
+
sorted_indices = sorted(range(len(fitness_scores)), key=lambda i: fitness_scores[i], reverse=True)
|
| 315 |
+
|
| 316 |
+
elite_count = int(self.cfg.elite_ratio * self.cfg.population_size)
|
| 317 |
+
elites = [self.population[i] for i in sorted_indices[:elite_count]]
|
| 318 |
+
|
| 319 |
+
new_population = elites.copy()
|
| 320 |
+
|
| 321 |
+
while len(new_population) < self.cfg.population_size:
|
| 322 |
+
if torch.rand(1) < 0.3 and len(elites) >= 2:
|
| 323 |
+
parent1, parent2 = torch.randperm(len(elites))[:2]
|
| 324 |
+
child = self.crossover(elites[parent1], elites[parent2])
|
| 325 |
+
else:
|
| 326 |
+
parent_idx = torch.randint(0, elite_count, (1,)).item()
|
| 327 |
+
parent = elites[parent_idx]
|
| 328 |
+
|
| 329 |
+
if torch.rand(1) < 0.5:
|
| 330 |
+
child = self.mutate_parameters(parent)
|
| 331 |
+
else:
|
| 332 |
+
new_cfg = self.mutate_architecture(parent.cfg)
|
| 333 |
+
child = NeuralTuringMachine(new_cfg).to(self.cfg.device)
|
| 334 |
+
|
| 335 |
+
new_population.append(child)
|
| 336 |
+
|
| 337 |
+
self.population = new_population[:self.cfg.population_size]
|
| 338 |
+
self.generation += 1
|
| 339 |
+
|
| 340 |
+
best_fitness = max(fitness_scores)
|
| 341 |
+
avg_fitness = sum(fitness_scores) / len(fitness_scores)
|
| 342 |
+
self.best_fitness = max(self.best_fitness, best_fitness)
|
| 343 |
+
|
| 344 |
+
return {
|
| 345 |
+
'generation': self.generation,
|
| 346 |
+
'best_fitness': best_fitness,
|
| 347 |
+
'avg_fitness': avg_fitness,
|
| 348 |
+
'best_ever': self.best_fitness
|
| 349 |
+
}
|
| 350 |
+
|
| 351 |
+
def run_evolution(self) -> List[Dict[str, float]]:
|
| 352 |
+
self.initialize_population()
|
| 353 |
+
|
| 354 |
+
history = []
|
| 355 |
+
for gen in range(self.cfg.max_generations):
|
| 356 |
+
stats = self.evolve_generation()
|
| 357 |
+
history.append(stats)
|
| 358 |
+
|
| 359 |
+
if gen % 10 == 0:
|
| 360 |
+
print(f"Gen {gen}: Best={stats['best_fitness']:.4f}, Avg={stats['avg_fitness']:.4f}")
|
| 361 |
+
|
| 362 |
+
return history
|
| 363 |
+
|
| 364 |
+
def get_best_model(self) -> NeuralTuringMachine:
|
| 365 |
+
fitness_scores = []
|
| 366 |
+
for ntm in self.population:
|
| 367 |
+
fitness = self.evaluator.evaluate_fitness(ntm)
|
| 368 |
+
fitness_scores.append(fitness['composite'])
|
| 369 |
+
|
| 370 |
+
best_idx = max(range(len(fitness_scores)), key=lambda i: fitness_scores[i])
|
| 371 |
+
return self.population[best_idx]
|
evolutionary_turing_docs.py
ADDED
|
@@ -0,0 +1,955 @@
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1 |
+
############################################################################################################################################
|
| 2 |
+
#|| - - - |8.19.2025| - - - || Evolutionary Turing Machine || - - - | 1990two | - - -||#
|
| 3 |
+
############################################################################################################################################
|
| 4 |
+
"""
|
| 5 |
+
Mathematical Foundation & Conceptual Documentation
|
| 6 |
+
-------------------------------------------------
|
| 7 |
+
|
| 8 |
+
CORE PRINCIPLE:
|
| 9 |
+
Combines Neural Turing Machines (external memory architectures) with evolutionary
|
| 10 |
+
algorithms to create adaptive memory systems that evolve both their architecture
|
| 11 |
+
and parameters through natural selection, enabling discovery of optimal memory
|
| 12 |
+
access patterns and computational structures.
|
| 13 |
+
|
| 14 |
+
MATHEMATICAL FOUNDATION:
|
| 15 |
+
=======================
|
| 16 |
+
|
| 17 |
+
1. NEURAL TURING MACHINE DYNAMICS:
|
| 18 |
+
Content-based addressing: w_t^c = softmax(Ξ²_t β K[M_t, k_t])
|
| 19 |
+
Where:
|
| 20 |
+
- w_t: attention weights over memory locations
|
| 21 |
+
- Ξ²_t: key strength (focus parameter)
|
| 22 |
+
- K[M,k]: cosine similarity between memory M and key k
|
| 23 |
+
- M_t: memory matrix at time t
|
| 24 |
+
- k_t: generated key vector
|
| 25 |
+
|
| 26 |
+
2. MEMORY OPERATIONS:
|
| 27 |
+
Read: r_t = Ξ£_i w_t^r[i] Γ M_t[i]
|
| 28 |
+
Erase: MΜ_t[i] = M_{t-1}[i] β (1 - w_t^w[i] β e_t)
|
| 29 |
+
Add: M_t[i] = MΜ_t[i] + w_t^w[i] β a_t
|
| 30 |
+
|
| 31 |
+
Where:
|
| 32 |
+
- r_t: read vector
|
| 33 |
+
- e_t: erase vector β [0,1]^M
|
| 34 |
+
- a_t: add vector β β^M
|
| 35 |
+
- β: element-wise product
|
| 36 |
+
|
| 37 |
+
3. EVOLUTIONARY FITNESS:
|
| 38 |
+
F(individual) = Ξ±Β·task_performance + Ξ²Β·memory_efficiency + Ξ³Β·stability
|
| 39 |
+
|
| 40 |
+
Where:
|
| 41 |
+
- task_performance: accuracy on computational tasks
|
| 42 |
+
- memory_efficiency: 1/(parameter_count/baseline)
|
| 43 |
+
- stability: consistency across multiple runs
|
| 44 |
+
|
| 45 |
+
4. GENETIC OPERATIONS:
|
| 46 |
+
Architecture Crossover: A_child = random_blend(A_parent1, A_parent2)
|
| 47 |
+
Parameter Mutation: ΞΈ'_i = ΞΈ_i + Ρ·N(0,ΟΒ²) with probability p_mut
|
| 48 |
+
Selection: P(selection) β exp(F(individual)/T)
|
| 49 |
+
|
| 50 |
+
Where T is selection temperature.
|
| 51 |
+
|
| 52 |
+
5. POPULATION DYNAMICS:
|
| 53 |
+
Elite Preservation: Keep top k% individuals
|
| 54 |
+
Tournament Selection: Choose parents via tournament
|
| 55 |
+
Replacement Strategy: (ΞΌ + Ξ») evolution strategy
|
| 56 |
+
|
| 57 |
+
CONCEPTUAL REASONING:
|
| 58 |
+
====================
|
| 59 |
+
|
| 60 |
+
WHY EVOLUTIONARY + TURING MACHINES?
|
| 61 |
+
- Fixed NTM architectures may be suboptimal for specific tasks
|
| 62 |
+
- Manual architecture design is time-intensive and domain-specific
|
| 63 |
+
- Evolution can discover novel memory access patterns
|
| 64 |
+
- Natural selection optimizes both structure and parameters simultaneously
|
| 65 |
+
|
| 66 |
+
KEY INNOVATIONS:
|
| 67 |
+
1. **Evolvable Architecture**: Memory size, heads, controller complexity all mutable
|
| 68 |
+
2. **Task-Adaptive Evolution**: Fitness functions guide toward task-specific solutions
|
| 69 |
+
3. **Multi-Objective Optimization**: Balance performance, efficiency, and stability
|
| 70 |
+
4. **Hierarchical Mutation**: Different rates for architecture vs parameters
|
| 71 |
+
5. **Memory Access Pattern Evolution**: Learn optimal attention strategies
|
| 72 |
+
|
| 73 |
+
APPLICATIONS:
|
| 74 |
+
- Algorithmic learning (sorting, copying, associative recall)
|
| 75 |
+
- Adaptive control systems with memory requirements
|
| 76 |
+
- Meta-learning for memory-augmented architectures
|
| 77 |
+
- Neural architecture search for sequence modeling
|
| 78 |
+
- Continual learning with evolving memory structures
|
| 79 |
+
|
| 80 |
+
COMPLEXITY ANALYSIS:
|
| 81 |
+
- Individual Evaluation: O(TΒ·(DΒ² + MΒ·H)) where T=sequence length, D=hidden size, M=memory slots, H=heads
|
| 82 |
+
- Population Evolution: O(PΒ·evaluations) where P=population size
|
| 83 |
+
- Architecture Mutation: O(1) for parameter changes, O(M) for structural changes
|
| 84 |
+
- Memory: O(PΒ·(DΒ² + MΒ²)) for population storage
|
| 85 |
+
|
| 86 |
+
BIOLOGICAL INSPIRATION:
|
| 87 |
+
- Neural plasticity and synaptic evolution
|
| 88 |
+
- Natural selection of neural circuits
|
| 89 |
+
- Memory consolidation and forgetting mechanisms
|
| 90 |
+
- Adaptive brain architecture development
|
| 91 |
+
"""
|
| 92 |
+
|
| 93 |
+
from __future__ import annotations
|
| 94 |
+
|
| 95 |
+
from dataclasses import dataclass
|
| 96 |
+
from typing import Dict, List, Optional, Tuple, Union
|
| 97 |
+
import math
|
| 98 |
+
import torch
|
| 99 |
+
import torch.nn as nn
|
| 100 |
+
import torch.nn.functional as F
|
| 101 |
+
from copy import deepcopy
|
| 102 |
+
|
| 103 |
+
|
| 104 |
+
@dataclass
|
| 105 |
+
class NTMConfig:
|
| 106 |
+
"""Configuration for Neural Turing Machine architecture.
|
| 107 |
+
|
| 108 |
+
Defines the structure and hyperparameters for a single NTM individual
|
| 109 |
+
in the evolutionary population. All parameters are evolvable.
|
| 110 |
+
"""
|
| 111 |
+
input_dim: int
|
| 112 |
+
output_dim: int
|
| 113 |
+
controller_dim: int = 128
|
| 114 |
+
controller_layers: int = 1
|
| 115 |
+
memory_slots: int = 128
|
| 116 |
+
memory_dim: int = 32
|
| 117 |
+
heads_read: int = 1
|
| 118 |
+
heads_write: int = 1
|
| 119 |
+
init_std: float = 0.1
|
| 120 |
+
|
| 121 |
+
############################################################################################################################################
|
| 122 |
+
#################################################### - - - Neural Turing Machine - - - ###############################################
|
| 123 |
+
|
| 124 |
+
class NeuralTuringMachine(nn.Module):
|
| 125 |
+
"""Neural Turing Machine with external memory and attention mechanisms.
|
| 126 |
+
|
| 127 |
+
Implements the complete NTM architecture including:
|
| 128 |
+
- LSTM controller for sequence processing
|
| 129 |
+
- External memory matrix with read/write operations
|
| 130 |
+
- Content-based addressing via cosine similarity
|
| 131 |
+
- Differentiable memory operations (erase, add)
|
| 132 |
+
|
| 133 |
+
Mathematical Details:
|
| 134 |
+
- Controller processes input + read vectors: h_t = LSTM(x_t β r_{t-1}, h_{t-1})
|
| 135 |
+
- Interface parameters: keys, strengths, erase/add vectors
|
| 136 |
+
- Attention: w_t = softmax(Ξ²_t β cosine_sim(M_t, k_t))
|
| 137 |
+
- Memory updates preserve differentiability for gradient-based learning
|
| 138 |
+
"""
|
| 139 |
+
def __init__(self, cfg: NTMConfig):
|
| 140 |
+
super().__init__()
|
| 141 |
+
self.cfg = cfg
|
| 142 |
+
R, W, Dm = cfg.heads_read, cfg.heads_write, cfg.memory_dim
|
| 143 |
+
|
| 144 |
+
# Controller: processes input + read vectors
|
| 145 |
+
ctrl_in = cfg.input_dim + R * Dm
|
| 146 |
+
self.controller = nn.LSTMCell(ctrl_in, cfg.controller_dim)
|
| 147 |
+
|
| 148 |
+
# Interface: generates read/write parameters
|
| 149 |
+
iface_read = R * (Dm + 1) # key + strength per read head
|
| 150 |
+
iface_write = W * (Dm + 1 + Dm + Dm) # key + strength + erase + add per write head
|
| 151 |
+
self.interface = nn.Linear(cfg.controller_dim, iface_read + iface_write)
|
| 152 |
+
|
| 153 |
+
# Output head: combines controller state + read vectors
|
| 154 |
+
self.output = nn.Linear(cfg.controller_dim + R * Dm, cfg.output_dim)
|
| 155 |
+
|
| 156 |
+
self.reset_parameters()
|
| 157 |
+
|
| 158 |
+
def reset_parameters(self):
|
| 159 |
+
"""Initialize parameters with appropriate distributions.
|
| 160 |
+
|
| 161 |
+
Uses Xavier initialization for linear layers and orthogonal
|
| 162 |
+
initialization for LSTM recurrent weights to ensure stable training.
|
| 163 |
+
Forget gate bias is initialized to 1.0 for better gradient flow.
|
| 164 |
+
"""
|
| 165 |
+
for m in self.modules():
|
| 166 |
+
if isinstance(m, nn.Linear):
|
| 167 |
+
nn.init.xavier_uniform_(m.weight)
|
| 168 |
+
nn.init.zeros_(m.bias)
|
| 169 |
+
if isinstance(m, nn.LSTMCell):
|
| 170 |
+
nn.init.xavier_uniform_(m.weight_ih)
|
| 171 |
+
nn.init.orthogonal_(m.weight_hh)
|
| 172 |
+
nn.init.zeros_(m.bias_ih)
|
| 173 |
+
nn.init.zeros_(m.bias_hh)
|
| 174 |
+
# Forget gate bias = 1.0 for better gradient flow
|
| 175 |
+
hs = m.bias_ih.shape[0] // 4
|
| 176 |
+
m.bias_ih.data[hs:2*hs].fill_(1.0)
|
| 177 |
+
m.bias_hh.data[hs:2*hs].fill_(1.0)
|
| 178 |
+
|
| 179 |
+
def initial_state(self, batch_size: int, device=None):
|
| 180 |
+
"""Initialize NTM state including memory, attention weights, and controller state.
|
| 181 |
+
|
| 182 |
+
Args:
|
| 183 |
+
batch_size: Number of parallel sequences
|
| 184 |
+
device: Target device for tensors
|
| 185 |
+
|
| 186 |
+
Returns:
|
| 187 |
+
Dictionary containing:
|
| 188 |
+
- M: Memory matrix [batch_size, memory_slots, memory_dim]
|
| 189 |
+
- w_r: Read attention weights [batch_size, heads_read, memory_slots]
|
| 190 |
+
- w_w: Write attention weights [batch_size, heads_write, memory_slots]
|
| 191 |
+
- r: Read vectors [batch_size, heads_read, memory_dim]
|
| 192 |
+
- h, c: LSTM controller states
|
| 193 |
+
"""
|
| 194 |
+
cfg = self.cfg
|
| 195 |
+
device = device or next(self.parameters()).device
|
| 196 |
+
|
| 197 |
+
# Initialize memory with small random values
|
| 198 |
+
M = torch.zeros(batch_size, cfg.memory_slots, cfg.memory_dim, device=device)
|
| 199 |
+
if cfg.init_std > 0:
|
| 200 |
+
M.normal_(0.0, cfg.init_std)
|
| 201 |
+
|
| 202 |
+
# Initialize attention weights uniformly (all locations equally attended)
|
| 203 |
+
w_r = torch.ones(batch_size, cfg.heads_read, cfg.memory_slots, device=device) / cfg.memory_slots
|
| 204 |
+
w_w = torch.ones(batch_size, cfg.heads_write, cfg.memory_slots, device=device) / cfg.memory_slots
|
| 205 |
+
|
| 206 |
+
# Initialize read vectors and controller states
|
| 207 |
+
r = torch.zeros(batch_size, cfg.heads_read, cfg.memory_dim, device=device)
|
| 208 |
+
h = torch.zeros(batch_size, cfg.controller_dim, device=device)
|
| 209 |
+
c = torch.zeros(batch_size, cfg.controller_dim, device=device)
|
| 210 |
+
|
| 211 |
+
return {'M': M, 'w_r': w_r, 'w_w': w_w, 'r': r, 'h': h, 'c': c}
|
| 212 |
+
|
| 213 |
+
def step(self, x: torch.Tensor, state: Dict[str, torch.Tensor]):
|
| 214 |
+
"""Execute one forward step of NTM computation.
|
| 215 |
+
|
| 216 |
+
Complete NTM forward pass:
|
| 217 |
+
1. Controller processes input + previous reads
|
| 218 |
+
2. Interface generates memory operation parameters
|
| 219 |
+
3. Content-based addressing computes attention weights
|
| 220 |
+
4. Memory operations (read, erase, add)
|
| 221 |
+
5. Output generation
|
| 222 |
+
|
| 223 |
+
Args:
|
| 224 |
+
x: Input tensor [batch_size, input_dim]
|
| 225 |
+
state: Current NTM state dictionary
|
| 226 |
+
|
| 227 |
+
Returns:
|
| 228 |
+
y: Output tensor [batch_size, output_dim]
|
| 229 |
+
new_state: Updated state dictionary
|
| 230 |
+
"""
|
| 231 |
+
cfg = self.cfg
|
| 232 |
+
B = x.shape[0]
|
| 233 |
+
|
| 234 |
+
# Step 1: Controller forward pass
|
| 235 |
+
ctrl_in = torch.cat([x, state['r'].view(B, -1)], dim=-1)
|
| 236 |
+
h, c = self.controller(ctrl_in, (state['h'], state['c']))
|
| 237 |
+
|
| 238 |
+
# Step 2: Generate interface parameters
|
| 239 |
+
iface = self.interface(h)
|
| 240 |
+
R, W, Dm = cfg.heads_read, cfg.heads_write, cfg.memory_dim
|
| 241 |
+
|
| 242 |
+
# Parse interface outputs
|
| 243 |
+
offset = 0
|
| 244 |
+
# Read parameters: keys and strengths
|
| 245 |
+
k_r = iface[:, offset:offset + R * Dm].view(B, R, Dm)
|
| 246 |
+
offset += R * Dm
|
| 247 |
+
beta_r = F.softplus(iface[:, offset:offset + R])
|
| 248 |
+
offset += R
|
| 249 |
+
|
| 250 |
+
# Write parameters: keys, strengths, erase vectors, add vectors
|
| 251 |
+
k_w = iface[:, offset:offset + W * Dm].view(B, W, Dm)
|
| 252 |
+
offset += W * Dm
|
| 253 |
+
beta_w = F.softplus(iface[:, offset:offset + W])
|
| 254 |
+
offset += W
|
| 255 |
+
erase = torch.sigmoid(iface[:, offset:offset + W * Dm]).view(B, W, Dm)
|
| 256 |
+
offset += W * Dm
|
| 257 |
+
add = torch.tanh(iface[:, offset:offset + W * Dm]).view(B, W, Dm)
|
| 258 |
+
|
| 259 |
+
def address(M, k, beta, prev_weight=None):
|
| 260 |
+
"""Content-based addressing mechanism.
|
| 261 |
+
|
| 262 |
+
Computes attention weights using cosine similarity between
|
| 263 |
+
memory contents and generated keys, focused by strength parameter.
|
| 264 |
+
|
| 265 |
+
Mathematical Details:
|
| 266 |
+
- Cosine similarity: sim(M[i], k) = (M[i] Β· k) / (||M[i]|| ||k||)
|
| 267 |
+
- Focused attention: w = softmax(Ξ² β sim)
|
| 268 |
+
- Optional momentum: adds small fraction of previous weights
|
| 269 |
+
|
| 270 |
+
Args:
|
| 271 |
+
M: Memory matrix [batch_size, slots, memory_dim]
|
| 272 |
+
k: Key vectors [batch_size, heads, memory_dim]
|
| 273 |
+
beta: Strength parameters [batch_size, heads]
|
| 274 |
+
prev_weight: Previous attention weights for momentum
|
| 275 |
+
|
| 276 |
+
Returns:
|
| 277 |
+
Attention weights [batch_size, heads, slots]
|
| 278 |
+
"""
|
| 279 |
+
# Normalize for cosine similarity
|
| 280 |
+
M_norm = torch.norm(M, dim=-1, keepdim=True).clamp_min(1e-8)
|
| 281 |
+
k_norm = torch.norm(k, dim=-1, keepdim=True).clamp_min(1e-8)
|
| 282 |
+
|
| 283 |
+
# Cosine similarity: M[i] Β· k / (||M[i]|| ||k||)
|
| 284 |
+
cos_sim = torch.sum(M.unsqueeze(1) * k.unsqueeze(2), dim=-1) / (
|
| 285 |
+
M_norm.squeeze(-1).unsqueeze(1) * k_norm.squeeze(-1).unsqueeze(-1)
|
| 286 |
+
)
|
| 287 |
+
|
| 288 |
+
# Apply strength and optional momentum
|
| 289 |
+
content_logits = beta.unsqueeze(-1) * cos_sim
|
| 290 |
+
if prev_weight is not None:
|
| 291 |
+
content_logits = content_logits + 0.02 * prev_weight # Small momentum term
|
| 292 |
+
|
| 293 |
+
return F.softmax(content_logits, dim=-1)
|
| 294 |
+
|
| 295 |
+
# Step 3: Compute attention weights
|
| 296 |
+
w_r = address(state['M'], k_r, beta_r, prev_weight=state.get('w_r'))
|
| 297 |
+
w_w = address(state['M'], k_w, beta_w, prev_weight=state.get('w_w'))
|
| 298 |
+
|
| 299 |
+
# Step 4: Memory operations
|
| 300 |
+
# Read: weighted sum over memory locations
|
| 301 |
+
r = torch.sum(w_r.unsqueeze(-1) * state['M'].unsqueeze(1), dim=2)
|
| 302 |
+
|
| 303 |
+
# Write: erase then add
|
| 304 |
+
M = state['M']
|
| 305 |
+
if W > 0:
|
| 306 |
+
# Erase: M[i] := M[i] β (1 - w[i] β e)
|
| 307 |
+
erase_term = torch.prod(1 - w_w.unsqueeze(-1) * erase.unsqueeze(2), dim=1)
|
| 308 |
+
M = M * erase_term
|
| 309 |
+
|
| 310 |
+
# Add: M[i] := M[i] + w[i] β a
|
| 311 |
+
add_term = torch.sum(w_w.unsqueeze(-1) * add.unsqueeze(2), dim=1)
|
| 312 |
+
M = M + add_term
|
| 313 |
+
|
| 314 |
+
# Step 5: Generate output
|
| 315 |
+
y = self.output(torch.cat([h, r.view(B, -1)], dim=-1))
|
| 316 |
+
|
| 317 |
+
new_state = {'M': M, 'w_r': w_r, 'w_w': w_w, 'r': r, 'h': h, 'c': c}
|
| 318 |
+
return y, new_state
|
| 319 |
+
|
| 320 |
+
def forward(self, x: torch.Tensor, state=None):
|
| 321 |
+
"""Forward pass for single step or sequence.
|
| 322 |
+
|
| 323 |
+
Handles both single-step operation (for interactive use) and
|
| 324 |
+
sequence processing (for training/evaluation).
|
| 325 |
+
|
| 326 |
+
Args:
|
| 327 |
+
x: Input tensor [batch_size, input_dim] or [batch_size, seq_len, input_dim]
|
| 328 |
+
state: Optional initial state (created if None)
|
| 329 |
+
|
| 330 |
+
Returns:
|
| 331 |
+
For single step: (output, new_state)
|
| 332 |
+
For sequence: (output_sequence, final_state)
|
| 333 |
+
"""
|
| 334 |
+
if x.dim() == 2: # Single step
|
| 335 |
+
if state is None:
|
| 336 |
+
state = self.initial_state(x.shape[0], x.device)
|
| 337 |
+
return self.step(x, state)
|
| 338 |
+
|
| 339 |
+
# Sequence processing
|
| 340 |
+
B, T, _ = x.shape
|
| 341 |
+
if state is None:
|
| 342 |
+
state = self.initial_state(B, x.device)
|
| 343 |
+
|
| 344 |
+
outputs = []
|
| 345 |
+
for t in range(T):
|
| 346 |
+
y, state = self.step(x[:, t], state)
|
| 347 |
+
outputs.append(y)
|
| 348 |
+
|
| 349 |
+
return torch.stack(outputs, dim=1), state
|
| 350 |
+
|
| 351 |
+
@dataclass
|
| 352 |
+
class EvolutionaryTuringConfig:
|
| 353 |
+
"""Configuration for evolutionary optimization of NTM population.
|
| 354 |
+
|
| 355 |
+
Defines hyperparameters for the evolutionary algorithm including
|
| 356 |
+
population size, mutation rates, selection pressure, and fitness
|
| 357 |
+
evaluation parameters.
|
| 358 |
+
"""
|
| 359 |
+
population_size: int = 100
|
| 360 |
+
mutation_rate: float = 0.1
|
| 361 |
+
architecture_mutation_rate: float = 0.05
|
| 362 |
+
elite_ratio: float = 0.2
|
| 363 |
+
max_generations: int = 200
|
| 364 |
+
input_dim: int = 8
|
| 365 |
+
output_dim: int = 8
|
| 366 |
+
device: str = 'cpu'
|
| 367 |
+
seed: Optional[int] = None
|
| 368 |
+
|
| 369 |
+
############################################################################################################################################
|
| 370 |
+
################################################# - - - Fitness Evaluation - - - #####################################################
|
| 371 |
+
|
| 372 |
+
class FitnessEvaluator:
|
| 373 |
+
"""Comprehensive fitness evaluation for NTM individuals.
|
| 374 |
+
|
| 375 |
+
Evaluates NTM performance on multiple algorithmic tasks to assess
|
| 376 |
+
general computational capability. Includes efficiency penalties
|
| 377 |
+
to encourage compact, effective architectures.
|
| 378 |
+
|
| 379 |
+
Tasks:
|
| 380 |
+
1. Copy Task: Tests basic memory read/write capabilities
|
| 381 |
+
2. Associative Recall: Tests content-based memory access
|
| 382 |
+
3. Efficiency: Penalizes excessive parameters
|
| 383 |
+
|
| 384 |
+
Mathematical Details:
|
| 385 |
+
- Copy task measures sequence reproduction accuracy
|
| 386 |
+
- Associative recall tests key-value pair memory
|
| 387 |
+
- Composite fitness balances multiple objectives
|
| 388 |
+
"""
|
| 389 |
+
def __init__(self, device: str = 'cpu'):
|
| 390 |
+
self.device = device
|
| 391 |
+
|
| 392 |
+
def copy_task(self, ntm: NeuralTuringMachine, seq_len: int = 8, batch_size: int = 16) -> float:
|
| 393 |
+
"""Evaluate NTM on sequence copying task.
|
| 394 |
+
|
| 395 |
+
The copy task is fundamental for testing memory capabilities:
|
| 396 |
+
1. Present input sequence
|
| 397 |
+
2. Present delimiter (end-of-sequence marker)
|
| 398 |
+
3. Evaluate output sequence reproduction accuracy
|
| 399 |
+
|
| 400 |
+
Mathematical Details:
|
| 401 |
+
- Input: xβ, xβ, ..., xβ, delimiter
|
| 402 |
+
- Target: reproduce xβ, xβ, ..., xβ after delimiter
|
| 403 |
+
- Loss: MSE between predicted and target sequences
|
| 404 |
+
- Accuracy: 1 / (1 + loss) for bounded score β [0,1]
|
| 405 |
+
|
| 406 |
+
Args:
|
| 407 |
+
ntm: NTM individual to evaluate
|
| 408 |
+
seq_len: Length of sequences to copy
|
| 409 |
+
batch_size: Number of parallel sequences
|
| 410 |
+
|
| 411 |
+
Returns:
|
| 412 |
+
Copy task accuracy score β [0,1]
|
| 413 |
+
"""
|
| 414 |
+
with torch.no_grad():
|
| 415 |
+
# Generate random binary sequences
|
| 416 |
+
x = torch.randint(0, 2, (batch_size, seq_len, ntm.cfg.input_dim),
|
| 417 |
+
device=self.device, dtype=torch.float32)
|
| 418 |
+
|
| 419 |
+
# Add delimiter (end-of-sequence marker)
|
| 420 |
+
delimiter = torch.zeros(batch_size, 1, ntm.cfg.input_dim, device=self.device)
|
| 421 |
+
delimiter[:, :, -1] = 1 # Use last dimension as delimiter signal
|
| 422 |
+
|
| 423 |
+
# Complete input: sequence + delimiter
|
| 424 |
+
input_seq = torch.cat([x, delimiter], dim=1)
|
| 425 |
+
|
| 426 |
+
try:
|
| 427 |
+
output, _ = ntm(input_seq)
|
| 428 |
+
|
| 429 |
+
# Compare output to target (original sequence)
|
| 430 |
+
T = seq_len
|
| 431 |
+
D = ntm.cfg.output_dim
|
| 432 |
+
pred = output[:, -T:, :D] # Last T outputs
|
| 433 |
+
|
| 434 |
+
# Handle dimension mismatch by using overlap
|
| 435 |
+
d = min(ntm.cfg.input_dim, D)
|
| 436 |
+
loss = F.mse_loss(pred[..., :d], x[..., :d])
|
| 437 |
+
accuracy = 1.0 / (1.0 + loss.item())
|
| 438 |
+
return accuracy
|
| 439 |
+
except:
|
| 440 |
+
# Return zero for failed evaluations (architecture issues)
|
| 441 |
+
return 0.0
|
| 442 |
+
|
| 443 |
+
def associative_recall(self, ntm: NeuralTuringMachine, num_pairs: int = 4) -> float:
|
| 444 |
+
"""Evaluate NTM on associative memory recall task.
|
| 445 |
+
|
| 446 |
+
Tests content-based memory access by storing key-value pairs
|
| 447 |
+
and then querying with keys to retrieve associated values.
|
| 448 |
+
|
| 449 |
+
Task Structure:
|
| 450 |
+
1. Store phase: present key-value pairs
|
| 451 |
+
2. Query phase: present keys (with zero values)
|
| 452 |
+
3. Evaluate: check if correct values are recalled
|
| 453 |
+
|
| 454 |
+
Mathematical Details:
|
| 455 |
+
- Keys: kβ, kβ, ..., kβ (half of input dimension)
|
| 456 |
+
- Values: vβ, vβ, ..., vβ (other half of input dimension)
|
| 457 |
+
- Query: present [kβ, 0], expect output [0, vβ]
|
| 458 |
+
- Score based on MSE between recalled and target values
|
| 459 |
+
|
| 460 |
+
Args:
|
| 461 |
+
ntm: NTM individual to evaluate
|
| 462 |
+
num_pairs: Number of key-value pairs to store/recall
|
| 463 |
+
|
| 464 |
+
Returns:
|
| 465 |
+
Associative recall accuracy score β [0,1]
|
| 466 |
+
"""
|
| 467 |
+
with torch.no_grad():
|
| 468 |
+
batch_size = 8
|
| 469 |
+
dim = ntm.cfg.input_dim
|
| 470 |
+
|
| 471 |
+
# Generate key-value pairs
|
| 472 |
+
keys = torch.randn(batch_size, num_pairs, dim // 2, device=self.device)
|
| 473 |
+
values = torch.randn(batch_size, num_pairs, dim // 2, device=self.device)
|
| 474 |
+
pairs = torch.cat([keys, values], dim=-1)
|
| 475 |
+
|
| 476 |
+
# Query format: keys with zero values
|
| 477 |
+
test_keys = torch.cat([keys, torch.zeros_like(values)], dim=-1)
|
| 478 |
+
expected_values = torch.cat([torch.zeros_like(keys), values], dim=-1)
|
| 479 |
+
|
| 480 |
+
# Complete sequence: store pairs then query
|
| 481 |
+
input_seq = torch.cat([pairs, test_keys], dim=1)
|
| 482 |
+
target_seq = torch.cat([torch.zeros_like(pairs), expected_values], dim=1)
|
| 483 |
+
|
| 484 |
+
try:
|
| 485 |
+
output, _ = ntm(input_seq)
|
| 486 |
+
|
| 487 |
+
# Evaluate query phase (second half of sequence)
|
| 488 |
+
D = ntm.cfg.output_dim
|
| 489 |
+
d = min(dim, D)
|
| 490 |
+
loss = F.mse_loss(output[:, num_pairs:, :d], target_seq[:, num_pairs:, :d])
|
| 491 |
+
accuracy = 1.0 / (1.0 + loss.item())
|
| 492 |
+
return accuracy
|
| 493 |
+
except:
|
| 494 |
+
return 0.0
|
| 495 |
+
|
| 496 |
+
def evaluate_fitness(self, ntm: NeuralTuringMachine) -> Dict[str, float]:
|
| 497 |
+
"""Comprehensive fitness evaluation across multiple criteria.
|
| 498 |
+
|
| 499 |
+
Evaluates individual on multiple tasks and efficiency metrics
|
| 500 |
+
to encourage both performance and architectural parsimony.
|
| 501 |
+
|
| 502 |
+
Fitness Components:
|
| 503 |
+
1. Copy Task (50%): Basic memory functionality
|
| 504 |
+
2. Associative Recall (30%): Content-based memory access
|
| 505 |
+
3. Efficiency (20%): Parameter count penalty
|
| 506 |
+
|
| 507 |
+
Mathematical Details:
|
| 508 |
+
- Each component scored β [0,1]
|
| 509 |
+
- Efficiency = 1 / (1 + params/baseline)
|
| 510 |
+
- Composite = weighted combination
|
| 511 |
+
|
| 512 |
+
Args:
|
| 513 |
+
ntm: NTM individual to evaluate
|
| 514 |
+
|
| 515 |
+
Returns:
|
| 516 |
+
Dictionary containing individual and composite fitness scores
|
| 517 |
+
"""
|
| 518 |
+
copy_score = self.copy_task(ntm)
|
| 519 |
+
recall_score = self.associative_recall(ntm)
|
| 520 |
+
|
| 521 |
+
# Efficiency penalty based on parameter count
|
| 522 |
+
param_count = sum(p.numel() for p in ntm.parameters())
|
| 523 |
+
efficiency = 1.0 / (1.0 + param_count / 100000) # Normalize to reasonable range
|
| 524 |
+
|
| 525 |
+
# Weighted composite fitness
|
| 526 |
+
composite_score = 0.5 * copy_score + 0.3 * recall_score + 0.2 * efficiency
|
| 527 |
+
|
| 528 |
+
return {
|
| 529 |
+
'copy': copy_score,
|
| 530 |
+
'recall': recall_score,
|
| 531 |
+
'efficiency': efficiency,
|
| 532 |
+
'composite': composite_score
|
| 533 |
+
}
|
| 534 |
+
|
| 535 |
+
###############################################################################################################################################
|
| 536 |
+
################################################# - - - Evolutionary Turing Machine - - - ###############################################
|
| 537 |
+
|
| 538 |
+
class EvolutionaryTuringMachine:
|
| 539 |
+
"""Evolutionary optimization system for Neural Turing Machine architectures.
|
| 540 |
+
|
| 541 |
+
Implements a complete evolutionary algorithm for discovering optimal
|
| 542 |
+
NTM architectures and parameters through natural selection. Uses
|
| 543 |
+
both architectural mutations (structure) and parameter mutations.
|
| 544 |
+
|
| 545 |
+
Evolutionary Operations:
|
| 546 |
+
1. Selection: Tournament/rank-based parent selection
|
| 547 |
+
2. Crossover: Architecture and parameter blending
|
| 548 |
+
3. Mutation: Structure modification and parameter perturbation
|
| 549 |
+
4. Replacement: Elite preservation with new offspring
|
| 550 |
+
|
| 551 |
+
The system evolves both the neural architecture (memory size, heads,
|
| 552 |
+
controller complexity) and the connection weights simultaneously.
|
| 553 |
+
"""
|
| 554 |
+
def __init__(self, cfg: EvolutionaryTuringConfig):
|
| 555 |
+
self.cfg = cfg
|
| 556 |
+
self.evaluator = FitnessEvaluator(cfg.device)
|
| 557 |
+
self.generation = 0
|
| 558 |
+
self.best_fitness = 0.0
|
| 559 |
+
self.population = []
|
| 560 |
+
|
| 561 |
+
if cfg.seed is not None:
|
| 562 |
+
torch.manual_seed(cfg.seed)
|
| 563 |
+
|
| 564 |
+
def create_random_config(self) -> NTMConfig:
|
| 565 |
+
"""Generate random NTM architecture configuration.
|
| 566 |
+
|
| 567 |
+
Creates diverse initial population by randomizing all
|
| 568 |
+
architectural hyperparameters within reasonable bounds.
|
| 569 |
+
|
| 570 |
+
Architectural Parameters:
|
| 571 |
+
- Controller dimension: [64, 256]
|
| 572 |
+
- Memory slots: [32, 256]
|
| 573 |
+
- Memory dimension: [16, 64]
|
| 574 |
+
- Read/write heads: [1, 4] and [1, 3]
|
| 575 |
+
|
| 576 |
+
Returns:
|
| 577 |
+
Random NTM configuration
|
| 578 |
+
"""
|
| 579 |
+
return NTMConfig(
|
| 580 |
+
input_dim=self.cfg.input_dim,
|
| 581 |
+
output_dim=self.cfg.output_dim,
|
| 582 |
+
controller_dim=torch.randint(64, 256, (1,)).item(),
|
| 583 |
+
controller_layers=torch.randint(1, 3, (1,)).item(),
|
| 584 |
+
memory_slots=torch.randint(32, 256, (1,)).item(),
|
| 585 |
+
memory_dim=torch.randint(16, 64, (1,)).item(),
|
| 586 |
+
heads_read=torch.randint(1, 4, (1,)).item(),
|
| 587 |
+
heads_write=torch.randint(1, 3, (1,)).item(),
|
| 588 |
+
init_std=0.1
|
| 589 |
+
)
|
| 590 |
+
|
| 591 |
+
def mutate_architecture(self, cfg: NTMConfig) -> NTMConfig:
|
| 592 |
+
"""Apply architectural mutations to NTM configuration.
|
| 593 |
+
|
| 594 |
+
Modifies structural parameters with probability architecture_mutation_rate.
|
| 595 |
+
Each architectural parameter can be independently mutated with
|
| 596 |
+
small random perturbations.
|
| 597 |
+
|
| 598 |
+
Mutation Operations:
|
| 599 |
+
- Controller dimension: Β±32 units
|
| 600 |
+
- Memory slots: Β±16 units
|
| 601 |
+
- Memory dimension: Β±8 units
|
| 602 |
+
- Read/write heads: Β±1 head (within bounds)
|
| 603 |
+
|
| 604 |
+
Args:
|
| 605 |
+
cfg: Original NTM configuration
|
| 606 |
+
|
| 607 |
+
Returns:
|
| 608 |
+
Mutated NTM configuration
|
| 609 |
+
"""
|
| 610 |
+
new_cfg = deepcopy(cfg)
|
| 611 |
+
|
| 612 |
+
if torch.rand(1) < self.cfg.architecture_mutation_rate:
|
| 613 |
+
new_cfg.controller_dim = max(32, new_cfg.controller_dim + torch.randint(-32, 33, (1,)).item())
|
| 614 |
+
|
| 615 |
+
if torch.rand(1) < self.cfg.architecture_mutation_rate:
|
| 616 |
+
new_cfg.memory_slots = max(16, new_cfg.memory_slots + torch.randint(-16, 17, (1,)).item())
|
| 617 |
+
|
| 618 |
+
if torch.rand(1) < self.cfg.architecture_mutation_rate:
|
| 619 |
+
new_cfg.memory_dim = max(8, new_cfg.memory_dim + torch.randint(-8, 9, (1,)).item())
|
| 620 |
+
|
| 621 |
+
if torch.rand(1) < self.cfg.architecture_mutation_rate:
|
| 622 |
+
new_cfg.heads_read = max(1, min(4, new_cfg.heads_read + torch.randint(-1, 2, (1,)).item()))
|
| 623 |
+
|
| 624 |
+
if torch.rand(1) < self.cfg.architecture_mutation_rate:
|
| 625 |
+
new_cfg.heads_write = max(1, min(3, new_cfg.heads_write + torch.randint(-1, 2, (1,)).item()))
|
| 626 |
+
|
| 627 |
+
return new_cfg
|
| 628 |
+
|
| 629 |
+
def mutate_parameters(self, ntm: NeuralTuringMachine) -> NeuralTuringMachine:
|
| 630 |
+
"""Apply parameter mutations to NTM weights.
|
| 631 |
+
|
| 632 |
+
Performs Gaussian perturbations to network parameters with
|
| 633 |
+
probability mutation_rate per parameter. Creates a new NTM
|
| 634 |
+
instance to avoid modifying the original.
|
| 635 |
+
|
| 636 |
+
Mathematical Details:
|
| 637 |
+
- Each parameter p mutated with probability mutation_rate
|
| 638 |
+
- Mutation: p' = p + Ξ΅ where Ξ΅ ~ N(0, 0.01Β²)
|
| 639 |
+
- Preserves network architecture, only modifies weights
|
| 640 |
+
|
| 641 |
+
Args:
|
| 642 |
+
ntm: Original NTM individual
|
| 643 |
+
|
| 644 |
+
Returns:
|
| 645 |
+
New NTM with mutated parameters
|
| 646 |
+
"""
|
| 647 |
+
new_ntm = NeuralTuringMachine(ntm.cfg).to(self.cfg.device)
|
| 648 |
+
new_ntm.load_state_dict(deepcopy(ntm.state_dict()))
|
| 649 |
+
|
| 650 |
+
with torch.no_grad():
|
| 651 |
+
for p in new_ntm.parameters():
|
| 652 |
+
# Apply mutation mask (probability mutation_rate per element)
|
| 653 |
+
mask = (torch.rand_like(p) < self.cfg.mutation_rate)
|
| 654 |
+
p.add_(torch.randn_like(p) * 0.01 * mask)
|
| 655 |
+
|
| 656 |
+
return new_ntm
|
| 657 |
+
|
| 658 |
+
def crossover(self, parent1: NeuralTuringMachine, parent2: NeuralTuringMachine) -> NeuralTuringMachine:
|
| 659 |
+
"""Create offspring through architectural crossover.
|
| 660 |
+
|
| 661 |
+
Combines architectural features from two parents by randomly
|
| 662 |
+
selecting each architectural parameter from either parent.
|
| 663 |
+
The resulting offspring has a new random weight initialization.
|
| 664 |
+
|
| 665 |
+
Crossover Strategy:
|
| 666 |
+
- Each architectural parameter chosen from parent1 or parent2 (50% each)
|
| 667 |
+
- New weights initialized randomly (architectural crossover only)
|
| 668 |
+
- Alternative: could implement parameter-level crossover
|
| 669 |
+
|
| 670 |
+
Args:
|
| 671 |
+
parent1: First parent NTM
|
| 672 |
+
parent2: Second parent NTM
|
| 673 |
+
|
| 674 |
+
Returns:
|
| 675 |
+
Offspring NTM with hybrid architecture
|
| 676 |
+
"""
|
| 677 |
+
cfg1, cfg2 = parent1.cfg, parent2.cfg
|
| 678 |
+
|
| 679 |
+
# Create hybrid configuration
|
| 680 |
+
new_cfg = NTMConfig(
|
| 681 |
+
input_dim=self.cfg.input_dim,
|
| 682 |
+
output_dim=self.cfg.output_dim,
|
| 683 |
+
controller_dim=cfg1.controller_dim if torch.rand(1) < 0.5 else cfg2.controller_dim,
|
| 684 |
+
memory_slots=cfg1.memory_slots if torch.rand(1) < 0.5 else cfg2.memory_slots,
|
| 685 |
+
memory_dim=cfg1.memory_dim if torch.rand(1) < 0.5 else cfg2.memory_dim,
|
| 686 |
+
heads_read=cfg1.heads_read if torch.rand(1) < 0.5 else cfg2.heads_read,
|
| 687 |
+
heads_write=cfg1.heads_write if torch.rand(1) < 0.5 else cfg2.heads_write,
|
| 688 |
+
init_std=0.1
|
| 689 |
+
)
|
| 690 |
+
|
| 691 |
+
# Create new individual with hybrid architecture
|
| 692 |
+
child = NeuralTuringMachine(new_cfg).to(self.cfg.device)
|
| 693 |
+
return child
|
| 694 |
+
|
| 695 |
+
def initialize_population(self):
|
| 696 |
+
"""Create initial population with diverse random architectures.
|
| 697 |
+
|
| 698 |
+
Generates population_size individuals with random architectural
|
| 699 |
+
configurations to ensure diversity in the initial gene pool.
|
| 700 |
+
Each individual is initialized with different structural parameters.
|
| 701 |
+
"""
|
| 702 |
+
self.population = []
|
| 703 |
+
for _ in range(self.cfg.population_size):
|
| 704 |
+
cfg = self.create_random_config()
|
| 705 |
+
ntm = NeuralTuringMachine(cfg).to(self.cfg.device)
|
| 706 |
+
self.population.append(ntm)
|
| 707 |
+
|
| 708 |
+
def evolve_generation(self) -> Dict[str, float]:
|
| 709 |
+
"""Execute one generation of evolutionary optimization.
|
| 710 |
+
|
| 711 |
+
Complete generational evolution cycle:
|
| 712 |
+
1. Evaluate all individuals in population
|
| 713 |
+
2. Select elite individuals for survival
|
| 714 |
+
3. Generate offspring through crossover and mutation
|
| 715 |
+
4. Replace non-elite individuals with offspring
|
| 716 |
+
5. Update statistics and generation counter
|
| 717 |
+
|
| 718 |
+
Uses (ΞΌ + Ξ») evolution strategy with elite preservation
|
| 719 |
+
to ensure best solutions are never lost.
|
| 720 |
+
|
| 721 |
+
Returns:
|
| 722 |
+
Dictionary containing generation statistics
|
| 723 |
+
"""
|
| 724 |
+
# Step 1: Evaluate population fitness
|
| 725 |
+
fitness_scores = []
|
| 726 |
+
for ntm in self.population:
|
| 727 |
+
fitness = self.evaluator.evaluate_fitness(ntm)
|
| 728 |
+
fitness_scores.append(fitness['composite'])
|
| 729 |
+
|
| 730 |
+
# Step 2: Selection - sort by fitness (descending)
|
| 731 |
+
sorted_indices = sorted(range(len(fitness_scores)), key=lambda i: fitness_scores[i], reverse=True)
|
| 732 |
+
|
| 733 |
+
# Step 3: Elite preservation
|
| 734 |
+
elite_count = int(self.cfg.elite_ratio * self.cfg.population_size)
|
| 735 |
+
elites = [self.population[i] for i in sorted_indices[:elite_count]]
|
| 736 |
+
|
| 737 |
+
# Step 4: Generate offspring to fill remaining population
|
| 738 |
+
new_population = elites.copy()
|
| 739 |
+
|
| 740 |
+
while len(new_population) < self.cfg.population_size:
|
| 741 |
+
if torch.rand(1) < 0.3 and len(elites) >= 2:
|
| 742 |
+
# Crossover: select two random elite parents
|
| 743 |
+
parent1, parent2 = torch.randperm(len(elites))[:2]
|
| 744 |
+
child = self.crossover(elites[parent1], elites[parent2])
|
| 745 |
+
else:
|
| 746 |
+
# Mutation: select random elite parent
|
| 747 |
+
parent_idx = torch.randint(0, elite_count, (1,)).item()
|
| 748 |
+
parent = elites[parent_idx]
|
| 749 |
+
|
| 750 |
+
if torch.rand(1) < 0.5:
|
| 751 |
+
# Parameter mutation
|
| 752 |
+
child = self.mutate_parameters(parent)
|
| 753 |
+
else:
|
| 754 |
+
# Architectural mutation
|
| 755 |
+
new_cfg = self.mutate_architecture(parent.cfg)
|
| 756 |
+
child = NeuralTuringMachine(new_cfg).to(self.cfg.device)
|
| 757 |
+
|
| 758 |
+
new_population.append(child)
|
| 759 |
+
|
| 760 |
+
# Step 5: Update population and statistics
|
| 761 |
+
self.population = new_population[:self.cfg.population_size]
|
| 762 |
+
self.generation += 1
|
| 763 |
+
|
| 764 |
+
best_fitness = max(fitness_scores)
|
| 765 |
+
avg_fitness = sum(fitness_scores) / len(fitness_scores)
|
| 766 |
+
self.best_fitness = max(self.best_fitness, best_fitness)
|
| 767 |
+
|
| 768 |
+
return {
|
| 769 |
+
'generation': self.generation,
|
| 770 |
+
'best_fitness': best_fitness,
|
| 771 |
+
'avg_fitness': avg_fitness,
|
| 772 |
+
'best_ever': self.best_fitness
|
| 773 |
+
}
|
| 774 |
+
|
| 775 |
+
def run_evolution(self) -> List[Dict[str, float]]:
|
| 776 |
+
"""Execute complete evolutionary optimization run.
|
| 777 |
+
|
| 778 |
+
Runs evolution for max_generations, tracking progress and
|
| 779 |
+
printing periodic updates. Returns complete optimization
|
| 780 |
+
history for analysis and visualization.
|
| 781 |
+
|
| 782 |
+
Returns:
|
| 783 |
+
List of generation statistics dictionaries
|
| 784 |
+
"""
|
| 785 |
+
self.initialize_population()
|
| 786 |
+
|
| 787 |
+
history = []
|
| 788 |
+
for gen in range(self.cfg.max_generations):
|
| 789 |
+
stats = self.evolve_generation()
|
| 790 |
+
history.append(stats)
|
| 791 |
+
|
| 792 |
+
# Periodic progress reporting
|
| 793 |
+
if gen % 10 == 0:
|
| 794 |
+
print(f"Gen {gen}: Best={stats['best_fitness']:.4f}, Avg={stats['avg_fitness']:.4f}")
|
| 795 |
+
|
| 796 |
+
return history
|
| 797 |
+
|
| 798 |
+
def get_best_model(self) -> NeuralTuringMachine:
|
| 799 |
+
"""Retrieve the best individual from current population.
|
| 800 |
+
|
| 801 |
+
Evaluates all current individuals and returns the one
|
| 802 |
+
with highest composite fitness score.
|
| 803 |
+
|
| 804 |
+
Returns:
|
| 805 |
+
Best NTM individual from population
|
| 806 |
+
"""
|
| 807 |
+
fitness_scores = []
|
| 808 |
+
for ntm in self.population:
|
| 809 |
+
fitness = self.evaluator.evaluate_fitness(ntm)
|
| 810 |
+
fitness_scores.append(fitness['composite'])
|
| 811 |
+
|
| 812 |
+
best_idx = max(range(len(fitness_scores)), key=lambda i: fitness_scores[i])
|
| 813 |
+
return self.population[best_idx]
|
| 814 |
+
|
| 815 |
+
###########################################################################################################################################
|
| 816 |
+
##################################################- - - DEMO AND TESTING - - -#########################################################
|
| 817 |
+
|
| 818 |
+
def test_evolutionary_turing():
|
| 819 |
+
"""Comprehensive test of evolutionary NTM optimization."""
|
| 820 |
+
print(" Testing Evolutionary Turing Machine - Adaptive Memory Architecture Evolution")
|
| 821 |
+
print("=" * 90)
|
| 822 |
+
|
| 823 |
+
# Create evolutionary system
|
| 824 |
+
config = EvolutionaryTuringConfig(
|
| 825 |
+
population_size=20, # Small for demo
|
| 826 |
+
max_generations=30,
|
| 827 |
+
input_dim=8,
|
| 828 |
+
output_dim=8,
|
| 829 |
+
mutation_rate=0.15,
|
| 830 |
+
architecture_mutation_rate=0.1,
|
| 831 |
+
elite_ratio=0.3,
|
| 832 |
+
device='cpu'
|
| 833 |
+
)
|
| 834 |
+
|
| 835 |
+
system = EvolutionaryTuringMachine(config)
|
| 836 |
+
|
| 837 |
+
print(f"Created Evolutionary Turing System:")
|
| 838 |
+
print(f" - Population size: {config.population_size}")
|
| 839 |
+
print(f" - Max generations: {config.max_generations}")
|
| 840 |
+
print(f" - Architecture mutation rate: {config.architecture_mutation_rate}")
|
| 841 |
+
print(f" - Parameter mutation rate: {config.mutation_rate}")
|
| 842 |
+
print(f" - Elite preservation: {config.elite_ratio*100:.0f}%")
|
| 843 |
+
|
| 844 |
+
# Test individual components first
|
| 845 |
+
print("\n Testing individual NTM...")
|
| 846 |
+
test_config = system.create_random_config()
|
| 847 |
+
test_ntm = NeuralTuringMachine(test_config).to(config.device)
|
| 848 |
+
|
| 849 |
+
print(f"Random NTM architecture:")
|
| 850 |
+
print(f" - Controller: {test_config.controller_dim}D")
|
| 851 |
+
print(f" - Memory: {test_config.memory_slots} Γ {test_config.memory_dim}")
|
| 852 |
+
print(f" - Heads: {test_config.heads_read}R/{test_config.heads_write}W")
|
| 853 |
+
|
| 854 |
+
# Test fitness evaluation
|
| 855 |
+
fitness = system.evaluator.evaluate_fitness(test_ntm)
|
| 856 |
+
print(f"\nFitness evaluation:")
|
| 857 |
+
for task, score in fitness.items():
|
| 858 |
+
print(f" - {task.capitalize()}: {score:.3f}")
|
| 859 |
+
|
| 860 |
+
# Test evolutionary operations
|
| 861 |
+
print("\n Testing evolutionary operations...")
|
| 862 |
+
|
| 863 |
+
# Test mutation
|
| 864 |
+
mutated_ntm = system.mutate_parameters(test_ntm)
|
| 865 |
+
print("β Parameter mutation successful")
|
| 866 |
+
|
| 867 |
+
# Test architectural mutation
|
| 868 |
+
mutated_config = system.mutate_architecture(test_config)
|
| 869 |
+
print("β Architecture mutation successful")
|
| 870 |
+
|
| 871 |
+
# Test crossover
|
| 872 |
+
parent2_config = system.create_random_config()
|
| 873 |
+
parent2 = NeuralTuringMachine(parent2_config).to(config.device)
|
| 874 |
+
offspring = system.crossover(test_ntm, parent2)
|
| 875 |
+
print("β Crossover operation successful")
|
| 876 |
+
|
| 877 |
+
# Run short evolutionary optimization
|
| 878 |
+
print(f"\n Running evolutionary optimization...")
|
| 879 |
+
print("(This may take a few minutes)")
|
| 880 |
+
|
| 881 |
+
history = system.run_evolution()
|
| 882 |
+
|
| 883 |
+
print(f"\nEvolution completed!")
|
| 884 |
+
print(f" - Final generation: {system.generation}")
|
| 885 |
+
print(f" - Best fitness achieved: {system.best_fitness:.4f}")
|
| 886 |
+
|
| 887 |
+
# Analyze evolution progress
|
| 888 |
+
initial_fitness = history[0]['best_fitness']
|
| 889 |
+
final_fitness = history[-1]['best_fitness']
|
| 890 |
+
improvement = final_fitness - initial_fitness
|
| 891 |
+
|
| 892 |
+
print(f"\nEvolution analysis:")
|
| 893 |
+
print(f" - Initial best fitness: {initial_fitness:.4f}")
|
| 894 |
+
print(f" - Final best fitness: {final_fitness:.4f}")
|
| 895 |
+
print(f" - Total improvement: {improvement:.4f}")
|
| 896 |
+
print(f" - Average generation improvement: {improvement/len(history):.4f}")
|
| 897 |
+
|
| 898 |
+
# Get and analyze best individual
|
| 899 |
+
best_ntm = system.get_best_model()
|
| 900 |
+
best_fitness = system.evaluator.evaluate_fitness(best_ntm)
|
| 901 |
+
|
| 902 |
+
print(f"\nBest evolved architecture:")
|
| 903 |
+
print(f" - Controller: {best_ntm.cfg.controller_dim}D")
|
| 904 |
+
print(f" - Memory: {best_ntm.cfg.memory_slots} Γ {best_ntm.cfg.memory_dim}")
|
| 905 |
+
print(f" - Heads: {best_ntm.cfg.heads_read}R/{best_ntm.cfg.heads_write}W")
|
| 906 |
+
print(f" - Parameters: {sum(p.numel() for p in best_ntm.parameters()):,}")
|
| 907 |
+
|
| 908 |
+
print(f"\nBest individual performance:")
|
| 909 |
+
for task, score in best_fitness.items():
|
| 910 |
+
print(f" - {task.capitalize()}: {score:.4f}")
|
| 911 |
+
|
| 912 |
+
print("\n Evolutionary Turing Machine test completed!")
|
| 913 |
+
print("β Population initialization and diversity")
|
| 914 |
+
print("β Fitness evaluation on algorithmic tasks")
|
| 915 |
+
print("β Architectural and parameter mutations")
|
| 916 |
+
print("β Crossover and offspring generation")
|
| 917 |
+
print("β Elite preservation and selection")
|
| 918 |
+
print("β Multi-generational evolution and improvement")
|
| 919 |
+
|
| 920 |
+
return True
|
| 921 |
+
|
| 922 |
+
def architecture_evolution_demo():
|
| 923 |
+
"""Demonstrate architectural evolution patterns."""
|
| 924 |
+
print("\n" + "="*70)
|
| 925 |
+
print(" ARCHITECTURE EVOLUTION DEMONSTRATION")
|
| 926 |
+
print("="*70)
|
| 927 |
+
|
| 928 |
+
config = EvolutionaryTuringConfig(population_size=10, max_generations=10)
|
| 929 |
+
system = EvolutionaryTuringMachine(config)
|
| 930 |
+
|
| 931 |
+
# Generate diverse initial architectures
|
| 932 |
+
architectures = []
|
| 933 |
+
for _ in range(5):
|
| 934 |
+
cfg = system.create_random_config()
|
| 935 |
+
architectures.append(cfg)
|
| 936 |
+
|
| 937 |
+
print("Initial architecture diversity:")
|
| 938 |
+
for i, cfg in enumerate(architectures):
|
| 939 |
+
params = (cfg.controller_dim * cfg.controller_dim +
|
| 940 |
+
cfg.memory_slots * cfg.memory_dim)
|
| 941 |
+
print(f" Arch {i+1}: {cfg.controller_dim}D controller, {cfg.memory_slots}Γ{cfg.memory_dim} memory, {params:,} params")
|
| 942 |
+
|
| 943 |
+
# Show mutation effects
|
| 944 |
+
print("\nMutation examples:")
|
| 945 |
+
base_cfg = architectures[0]
|
| 946 |
+
for i in range(3):
|
| 947 |
+
mutated = system.mutate_architecture(base_cfg)
|
| 948 |
+
print(f" Mutation {i+1}: {mutated.controller_dim}D controller, {mutated.memory_slots}Γ{mutated.memory_dim} memory")
|
| 949 |
+
|
| 950 |
+
print("\n Evolution discovers optimal architectures through natural selection!")
|
| 951 |
+
print(" Larger controllers and memories often emerge for complex tasks")
|
| 952 |
+
|
| 953 |
+
if __name__ == "__main__":
|
| 954 |
+
test_evolutionary_turing()
|
| 955 |
+
architecture_evolution_demo()
|