188 lines
7.2 KiB
Python
188 lines
7.2 KiB
Python
"""
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Capacity-matched EDMA refinement (parameter budget equal to the
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attention scheme: 4 d^2 = 2.36M at d = 768).
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================================================================
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Four-head averaged gated refinement applied to the closed-form
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demultiplexer output:
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out = (1/4) sum_k D softmax(Q_k x / sqrt(D)) .* x,
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with Q_1..Q_4 in R^{D x D} (4 d^2 parameters, exactly the
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attention scheme's budget). The single-gate 0.59M refiner is the
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special case of four identical heads, so the family contains it
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by construction. Same training recipe: demux outputs from
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parametric pairs at beta = 0.028, Haar pool 32, Rayleigh
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channels, complex noise, training SNR uniform in [5, 25] dB,
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Adam 5e-4 with gradient clipping, batch 48, 200 epochs.
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Evaluation on the real BERT/ViT pairs with fresh Haar masks and
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200 fading draws per pair. Appends column `edma_ref2` to
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data/bertvit_merged.csv and prints all-curve numbers.
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"""
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from __future__ import annotations
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import csv
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import math
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import time
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import numpy as np
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import torch
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from fig_real_merged import load_pairs, cosine, SNRS, NFADE, D, DATA
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SEED = 2026
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rng = np.random.default_rng(SEED + 31)
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torch.manual_seed(SEED + 31)
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BETA0 = 0.028
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G0 = 1.0 - BETA0**2
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def haar_t(gen):
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Q, R = torch.linalg.qr(torch.randn(D, D, generator=gen))
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return Q * torch.sign(torch.diagonal(R))
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def train_refiner2(epochs=220, steps=20, batch=48, lr=5e-4,
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l2=0.5, l3=0.5, pool=32):
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"""Stage 1 trains a single gate (the proven 0.59M recipe); stage 2
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warm-starts four heads from it plus small perturbations and
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fine-tunes at a reduced learning rate, so the capacity-matched
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family starts at the single-gate solution it contains."""
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print(f"=== training capacity-matched refinement (4-head gate, "
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f"4d^2 = {4*D*D/1e6:.2f}M params, warm-started) ===",
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flush=True)
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gen = torch.Generator().manual_seed(SEED + 31)
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masks = []
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for _ in range(pool):
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U1, U2 = haar_t(gen), haar_t(gen)
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masks.append((U1.numpy(), (BETA0 * U1
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+ math.sqrt(G0) * U2).numpy()))
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Q0 = torch.nn.Parameter(torch.randn(D, D, generator=gen)
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/ math.sqrt(D))
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params = [Q0]
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opt = torch.optim.Adam(params, lr=lr)
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stage2_at = 120 # epochs of single-gate pre-training
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def forward(x):
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outs = [D * torch.softmax((x @ Qk.T) / math.sqrt(D), dim=1) * x
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for Qk in params]
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return sum(outs) / len(params)
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t0 = time.time()
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for ep in range(epochs):
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if ep == stage2_at:
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base = params[0].detach()
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params = [torch.nn.Parameter(
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base.clone() + 0.02 * torch.randn(D, D, generator=gen)
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/ math.sqrt(D)) for _ in range(4)]
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opt = torch.optim.Adam(params, lr=2e-4)
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print(f" [warm start] 4 heads initialised from the trained "
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f"gate at epoch {ep}", flush=True)
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for _ in range(steps):
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xs, ts = [], []
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for _ in range(batch):
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e1 = torch.nn.functional.normalize(
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torch.randn(D, generator=gen), dim=0).numpy()
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w = torch.randn(D, generator=gen).numpy()
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w = w - (w @ e1) * e1
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w = w / np.linalg.norm(w)
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e2 = BETA0 * e1 + math.sqrt(G0) * w
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M1, M2 = masks[int(torch.randint(pool, (1,),
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generator=gen))]
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snr = float(5.0 + 20.0 * torch.rand(1, generator=gen))
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sig = 10 ** (-snr / 20.0)
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h = (torch.randn(2, generator=gen).numpy()
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+ 1j * torch.randn(2, generator=gen).numpy()) \
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/ math.sqrt(2)
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nc = (torch.randn(D, generator=gen).numpy()
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+ 1j * torch.randn(D, generator=gen).numpy()) \
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/ math.sqrt(2)
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rc = h[0] * (M1 @ e1) + h[1] * (M2 @ e2) + sig * nc
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t1 = M1.T @ rc / h[0]
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t2 = M2.T @ rc / h[1]
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g1 = (t1 - BETA0 * (h[1] / h[0]) * t2) / G0
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xs.append(torch.tensor(np.real(g1), dtype=torch.float32))
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ts.append(torch.tensor(e1, dtype=torch.float32))
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x = torch.stack(xs); t = torch.stack(ts)
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out = forward(x)
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mse = ((out - t)**2).mean()
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cs = torch.nn.functional.cosine_similarity(out, t, dim=1).mean()
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loss = l2 * mse + l3 * (1.0 - cs)
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opt.zero_grad(); loss.backward()
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torch.nn.utils.clip_grad_norm_(params, 1.0)
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opt.step()
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if (ep + 1) % 50 == 0:
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print(f" epoch {ep+1}: loss {float(loss.detach()):.4f} "
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f"(cos {float(cs.detach()):.3f})", flush=True)
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print(f" trained in {time.time()-t0:.0f}s")
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return [p.detach().numpy() for p in params]
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def refine2(P, g):
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x = np.real(g)
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def gate(Q, v):
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sc = (Q @ v) / math.sqrt(D)
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sc = sc - sc.max()
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w = np.exp(sc); w /= w.sum()
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return D * w * v
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return sum(gate(Qk, x) for Qk in P) / 4.0
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def main():
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A, B, betas = load_pairs()
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P = train_refiner2()
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ref = np.zeros(len(SNRS)); cnt = 0
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t0 = time.time()
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for i in range(len(A)):
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e1, e2, bi = A[i], B[i], float(betas[i])
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gi = 1.0 - bi**2
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for f in range(NFADE):
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G1 = rng.standard_normal((D, D))
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Qh, Rh = np.linalg.qr(G1)
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U1 = Qh * np.sign(np.diag(Rh))
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G2 = rng.standard_normal((D, D))
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Qh, Rh = np.linalg.qr(G2)
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U2 = Qh * np.sign(np.diag(Rh))
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M1 = U1
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M2 = bi * U1 + math.sqrt(gi) * U2
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h = (rng.standard_normal(2) + 1j * rng.standard_normal(2)) \
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/ math.sqrt(2)
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h1, h2 = h
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r0 = h1 * (M1 @ e1) + h2 * (M2 @ e2)
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n = (rng.standard_normal(D) + 1j * rng.standard_normal(D)) \
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/ math.sqrt(2)
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for k, s in enumerate(SNRS):
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sig = 10 ** (-s / 20.0)
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r = r0 + sig * n
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t1 = M1.T @ r / h1; t2 = M2.T @ r / h2
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g1 = (t1 - bi * (h2 / h1) * t2) / gi
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g2 = (t2 - bi * (h1 / h2) * t1) / gi
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ref[k] += 0.5 * (cosine(refine2(P, g1), e1)
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+ cosine(refine2(P, g2), e2))
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cnt += 1
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print(f" pair {i+1}/{len(A)} done ({time.time()-t0:.0f}s)",
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flush=True)
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ref /= cnt
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rows = list(csv.DictReader(open(DATA / "bertvit_merged.csv")))
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names = list(rows[0].keys())
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if "edma_ref2" not in names:
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names.append("edma_ref2")
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for k, r in enumerate(rows):
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r["edma_ref2"] = f"{ref[k]}"
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with open(DATA / "bertvit_merged.csv", "w", newline="") as f:
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w = csv.DictWriter(f, fieldnames=names)
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w.writeheader(); w.writerows(rows)
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print("[OK] appended edma_ref2 to bertvit_merged.csv")
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for k, r in enumerate(rows):
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print(f" {float(r['snr_db']):4.0f} dB "
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f"EDMA {float(r['edma']):.3f} "
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f"ref(0.59M) {float(r['edma_ref']):.3f} "
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f"ref2(2.36M) {ref[k]:.3f} "
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f"ATT(2.36M) {float(r['att']):.3f} "
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f"genie {float(r['genie']):.3f}")
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if __name__ == "__main__":
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main()
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