File size: 1,860 Bytes
1c1d9aa | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 | import torch, sys, json
sys.path.insert(0, "..")
from src.moo import cagrad_update_k2, raco_update_k2, _grads_dot, _solve_lambda_k2
w1, w2 = 0.8, 0.2
c = 0.4
for seed in range(200):
torch.manual_seed(seed)
g1 = torch.randn(100)
g2 = torch.randn(100)
H11 = _grads_dot([g1], [g1])
H12 = _grads_dot([g1], [g2])
H22 = _grads_dot([g2], [g2])
g0_norm_sq = (w1 * w1) * H11 + (2.0 * w1 * w2) * H12 + (w2 * w2) * H22
g0_norm = torch.sqrt(torch.clamp(g0_norm_sq, min=0.0))
b1 = (w1 * H11) + (w2 * H12)
b2 = (w1 * H12) + (w2 * H22)
s_val = float(g0_norm) * c
lam_raw, _ = _solve_lambda_k2(b1, b2, H11, H12, H22, s_val)
p1_raw = float(lam_raw)
p2_raw = 1.0 - float(lam_raw)
if 0.0 < p1_raw < 1.0 and p2_raw > w2:
# Clipping changes the ratio p1:p2
p1_clipped = min(p1_raw, w1)
p2_clipped = min(p2_raw, w2)
# Compute the actual update directions
cagrad_g = cagrad_update_k2([g1], [g2], w1, w2, c=c)
raco_g = raco_update_k2([g1], [g2], w1, w2, c=c)
diff_norm = float((cagrad_g[0] - raco_g[0]).norm().item())
if diff_norm > 1e-4:
g0 = g1 * w1 + g2 * w2
ca_dir = cagrad_g[0] / cagrad_g[0].norm()
ra_dir = raco_g[0] / raco_g[0].norm()
g0_dir = g0 / g0.norm()
print(f"seed={seed}: p_raw=({p1_raw:.3f},{p2_raw:.3f}) "
f"p_clipped=({p1_clipped:.3f},{p2_clipped:.3f}) "
f"diff_norm={diff_norm:.4f}")
print(f" CAGrad direction deviates from g0 by {float((ca_dir - g0_dir).norm().item()):.4f}")
print(f" RACO direction deviates from g0 by {float((ra_dir - g0_dir).norm().item()):.4f}")
break
else:
print("No clipping case found in 200 attempts - this is expected since the geometry often makes p_extreme=0 or 1")
|