DFA + residual-branch penalty test: seed=123, lam=0.0001
  ep 0: ||h_L||=8.791e+00 ||g_2||=9.848e-04 acc=0.0957
  ep 1: ||h_L||=2.827e+03 ||g_2||=3.043e-06 eval_acc=0.3262 test_acc=0.3037
  ep 10: ||h_L||=1.476e+04 ||g_2||=9.239e-07 eval_acc=0.3379 test_acc=0.3408
  ep 20: ||h_L||=1.954e+04 ||g_2||=7.765e-07 eval_acc=0.3604 test_acc=0.3606
  ep 30: ||h_L||=2.057e+04 ||g_2||=7.580e-07 eval_acc=0.3682 test_acc=0.3622

FINAL test acc: 0.3622
Compare to:
  DFA-vanilla (3-seed mean):    0.308
  DFA-shallow (3-seed mean):    0.349
  DFA-frozen (3-seed mean):     0.349
  BP-trainable (3-seed mean):   0.609
Saved results/dfa_pen_short/dfa_pen_lam0.0001_s123.json
Saved results/dfa_pen_short/dfa_pen_lam0.0001_s123.pt