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JSAC_AIRAN/c22_maml_epoch.py
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#!/usr/bin/env python3
# ============================================================
# c22_maml_epoch.py
#
# Meta-training trajectory for the signed MAML receiver on the
# MNIST TDL chain: warm-started from the converged joint model,
# the adapted SER at (15 dB, nu = 0.05) is recorded every
# ckpt-every meta-steps, extending the convergence figure of
# c19 beyond the joint-training phase.
# ============================================================
import argparse
import csv
import os
import numpy as np
import torch
import torch.nn.functional as F
import c11_doppler_csi as base
import c13_mnist as m13
@torch.no_grad()
def eval_adapted(model, fast, x, y, chan, X_pilot, args, device):
noise_var = 10 ** (-args.eval_snr / 10.0)
rng = np.random.default_rng(args.seed + 3)
errs, total = 0, 0
for _ in range(args.eval_nb):
imgs, labels = m13.sample_frames(x, y, args.eval_batch, args.users,
device, rng)
g_p, g_d = chan.sample(args.eval_batch, args.eval_fd, args.delta)
logits = m13.forward_frames_fast(model, fast, imgs, chan, g_p, g_d,
X_pilot, noise_var, args.eval_fd,
args.delta)
errs += (logits.argmax(-1) != labels).sum().item()
total += labels.numel()
return errs / total
def main():
p = argparse.ArgumentParser()
p.add_argument("--users", type=int, default=8)
p.add_argument("--dim", type=int, default=128)
p.add_argument("--hidden", type=int, default=256)
p.add_argument("--nfft", type=int, default=128)
p.add_argument("--cp", type=int, default=16)
p.add_argument("--taps", type=int, default=8)
p.add_argument("--delta", type=int, default=6)
p.add_argument("--train-snrs", type=float, nargs="+",
default=[0, 5, 10, 15, 20, 25])
p.add_argument("--train-fds", type=float, nargs="+",
default=[0.002, 0.005, 0.01, 0.02, 0.05, 0.1])
p.add_argument("--meta-steps", type=int, default=2500)
p.add_argument("--pretrain-steps", type=int, default=0)
p.add_argument("--ckpt-every", type=int, default=250)
p.add_argument("--meta-batch", type=int, default=4)
p.add_argument("--inner-lr", type=float, default=0.02)
p.add_argument("--batch", type=int, default=64)
p.add_argument("--lr", type=float, default=1e-3)
p.add_argument("--eval-inner-steps", type=int, default=5)
p.add_argument("--eval-inner-lr", type=float, default=0.01)
p.add_argument("--support", type=int, default=32)
p.add_argument("--eval-snr", type=float, default=15.0)
p.add_argument("--eval-fd", type=float, default=0.05)
p.add_argument("--eval-batch", type=int, default=64)
p.add_argument("--eval-nb", type=int, default=30)
p.add_argument("--seed", type=int, default=0)
p.add_argument("--save-dir", type=str, default="results_mnist")
p.add_argument("--data-root", type=str, default="data_mnist")
args = p.parse_args()
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
print("device:", device)
base.set_seed(args.seed)
tr, te = m13.get_datasets(args.data_root)
x_tr, y_tr = m13.tensorize(tr)
x_te, y_te = m13.tensorize(te)
chan = base.TDLChannel(args.nfft, args.cp, args.taps, device=device)
X_pilot = base.make_pilot(args.nfft, device)
model = m13.MnistSemanticMA(args.users, args.dim, args.hidden).to(device)
rng = np.random.default_rng(args.seed)
if args.pretrain_steps > 0:
# retrace the joint training for the warm-start phase so that
# the meta phase continues the same trajectory as the joint curve
popt = torch.optim.Adam(model.parameters(), lr=1e-3)
for step in range(1, args.pretrain_steps + 1):
snr = float(rng.choice(args.train_snrs))
fd = float(rng.choice(args.train_fds))
imgs, labels = m13.sample_frames(x_tr, y_tr, args.batch,
args.users, device, rng)
g_p, g_d = chan.sample(args.batch, fd, args.delta)
noise_var = 10 ** (-snr / 10.0)
logits = m13.forward_frames(model, imgs, chan, g_p, g_d,
X_pilot, noise_var, fd, args.delta)
loss = F.cross_entropy(logits.reshape(-1, 10),
labels.reshape(-1))
popt.zero_grad(set_to_none=True)
loss.backward()
popt.step()
if step % 2000 == 0:
print(f"[pretrain {step}/{args.pretrain_steps}]", flush=True)
else:
model.load_state_dict(torch.load(
os.path.join(args.save_dir, "mnist_semantic.pt"),
map_location=device))
opt = torch.optim.Adam(model.parameters(), lr=args.lr)
def task_loss(fast, snr, fd):
imgs, labels = m13.sample_frames(x_tr, y_tr, args.batch, args.users,
device, rng)
g_p, g_d = chan.sample(args.batch, fd, args.delta)
noise_var = 10 ** (-snr / 10.0)
logits = m13.forward_frames_fast(model, fast, imgs, chan, g_p, g_d,
X_pilot, noise_var, fd, args.delta)
return F.cross_entropy(logits.reshape(-1, 10), labels.reshape(-1))
csv_path = os.path.join(args.save_dir, "mnist_maml_epoch.csv")
with open(csv_path, "w", newline="") as f:
w = csv.writer(f)
w.writerow(["step", "ser"])
fast0 = m13.adapt_mnist(model, x_tr, y_tr, chan, X_pilot, args,
args.eval_snr, device)
ser0 = eval_adapted(model, fast0, x_te, y_te, chan, X_pilot, args,
device)
w.writerow([args.pretrain_steps, ser0])
print(f"[meta 0] ser={ser0:.4e}", flush=True)
for step in range(1, args.meta_steps + 1):
meta_loss = 0.0
for _ in range(args.meta_batch):
snr, fd = base.sample_task(args, rng)
fast = {k: v for k, v in model.named_parameters()
if k.startswith(m13.MNIST_DECODER_KEYS_PREFIX)}
loss_sup = task_loss(fast, snr, fd)
grads = torch.autograd.grad(loss_sup, list(fast.values()))
fast = {k: p - args.inner_lr * g.detach()
for (k, p), g in zip(fast.items(), grads)}
meta_loss = meta_loss + task_loss(fast, snr, fd)
meta_loss = meta_loss / args.meta_batch
opt.zero_grad(set_to_none=True)
meta_loss.backward()
opt.step()
if step % args.ckpt_every == 0:
fastc = m13.adapt_mnist(model, x_tr, y_tr, chan, X_pilot,
args, args.eval_snr, device)
ser = eval_adapted(model, fastc, x_te, y_te, chan, X_pilot,
args, device)
w.writerow([args.pretrain_steps + step, ser])
f.flush()
print(f"[meta {step}/{args.meta_steps}] ser={ser:.4e}",
flush=True)
print("saved", csv_path)
if __name__ == "__main__":
main()