Alexi primer deck: 10 slides (arch op-by-op, EP phases, schedule/parallelism, 72M blowup from real logs, loop-gain + beta-window hypotheses, diagnostics table, in-flight outcomes, $50k ladder) + figure scripts

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014FAPDWQ49M5Ye3NpTndTpn

1 files changed, 99 insertions, 0 deletions

diff --git a/ep_run/fig_primer_phases.py b/ep_run/fig_primer_phases.py
new file mode 100644
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+++ b/ep_run/fig_primer_phases.py
@@ -0,0 +1,99 @@
+"""Slide variant of fig_primer_arch: free/nudged phases + update only (no model panel,
+no PC contrast). PDF/PNG/SVG to ../assets/."""
+import matplotlib
+matplotlib.use('Agg')
+import matplotlib.pyplot as plt
+plt.rcParams['svg.fonttype'] = 'none'   # keep text editable in PPT
+from matplotlib.patches import FancyBboxPatch
+
+INK   = '#3a3a3a'
+GRAY  = '#8a8a8a'
+BOXF  = '#f4f4f4'
+BOXE  = '#9a9a9a'
+BLUE  = '#2c6fbb'
+BLUEF = '#eaf1fa'
+ORAN  = '#d95f02'
+RED   = '#b03a2e'
+CREAM = '#faf6ee'
+CREME = '#c9b895'
+
+fig = plt.figure(figsize=(12.2, 11.0))
+ax = fig.add_axes([0, 0, 1, 1]); ax.set_xlim(0, 100); ax.set_ylim(16, 105); ax.axis('off')
+
+def box(x, y, w, h, fc=BOXF, ec=BOXE, lw=1.0, r=0.6):
+    b = FancyBboxPatch((x, y), w, h, boxstyle=f'round,pad=0.25,rounding_size={r}',
+                       fc=fc, ec=ec, lw=lw)
+    ax.add_patch(b); return b
+
+def txt(x, y, s, size=8.5, color=INK, ha='center', va='center', w='normal', style='normal'):
+    ax.text(x, y, s, fontsize=size, color=color, ha=ha, va=va,
+            fontweight=w, fontstyle=style)
+
+def arrow(x0, y0, x1, y1, color=INK, lw=1.2, style='-|>', ms=11):
+    ax.annotate('', xy=(x1, y1), xytext=(x0, y0),
+                arrowprops=dict(arrowstyle=style, color=color, lw=lw,
+                                mutation_scale=ms, shrinkA=0.5, shrinkB=0.5))
+
+def state_col(x0, ys, labels, notes, fc=BLUEF, ec=BLUE, note_c=GRAY):
+    for y, lab, note in zip(ys, labels, notes):
+        box(x0 - 10.5, y - 2.2, 21, 4.4, fc=fc, ec=ec, lw=1.2)
+        txt(x0, y, lab, 10, color=INK)
+        if note: txt(x0 + 12.2, y, note, 8.4, note_c, ha='left')
+    for ya, yb in zip(ys[1:], ys[:-1]):
+        arrow(x0, ya + 2.7, x0, yb - 2.8, lw=1.15)
+
+# ======================== free phase ========================
+bx = 25
+txt(bx, 102.3, 'Free phase  (= inference)', 11.5, w='bold')
+txt(bx, 99.4, 'give each layer a state $z_l$ (3 of $L$ drawn); settle the disagreement energy', 8.8, GRAY)
+txt(bx, 95.4, r'$E(z)\ =\ \sum_l\ \frac{1}{2}\,\|\,z_l - f_l(z_{l-1})\,\|^2$', 11.5)
+
+ys = [85, 73, 61]
+state_col(bx - 6, ys, [r'$z_3 = f_3(z_2)$', r'$z_2 = f_2(z_1)$', r'$z_1 = f_1(\mathrm{emb})$'],
+          ['term = 0', 'term = 0', 'term = 0'])
+arrow(bx - 6, 52.4, bx - 6, 58.0, lw=1.15)
+txt(bx - 6, 50.2, r'$\mathrm{emb}(x)$', 10)
+
+txt(bx, 43.8, 'The minimum is exact:  $E=0$,  states $\\equiv$ forward activations,', 9)
+txt(bx, 40.8, 'and one bottom-up pass reaches it.', 9)
+txt(bx, 37.2, 'The free phase adds nothing and changes nothing at inference.', 8.6, GRAY)
+
+# ======================== nudged phase ========================
+nx = 70
+txt(nx, 102.3, 'Nudged phase  (training only)', 11.5, w='bold')
+txt(nx, 99.4, r'add the loss at strength $\beta \ll 1$ and settle again:', 8.8, GRAY)
+txt(nx, 95.4, r'$E(z)\ +\ \beta\cdot\mathrm{CE}(\mathrm{logits}(z_3),\,y)$', 11.5)
+
+txt(nx + 3.0, 91.8, r'pull $-\beta\,\nabla\mathrm{CE}$', 9.4, RED, ha='left')
+txt(nx + 3.0, 89.4, '(the only place the label enters)', 7.8, RED, ha='left')
+arrow(nx + 2.0, 90.9, nx - 3.5, 87.8, color=RED, lw=1.6)
+
+nys = [85, 73, 61]
+state_col(nx - 6, nys,
+          [r'$z_3^{\beta} = z_3 + d_3$', r'$z_2^{\beta} = z_2 + d_2$', r'$z_1^{\beta} = z_1 + d_1$'],
+          [None, None, None], fc='#fdeee2', ec=ORAN)
+arrow(nx - 6, 52.4, nx - 6, 58.0, lw=1.15)
+txt(nx - 6, 50.2, r'$\mathrm{emb}(x)$', 10)
+
+for (ya, yb, lab) in [(83.0, 75.8, r'$d_2 = J_3^{\top} d_3$'),
+                      (71.0, 63.8, r'$d_1 = J_2^{\top} d_2$')]:
+    arrow(nx + 6.4, ya, nx + 6.4, yb, color=ORAN, lw=1.6)
+    txt(nx + 8.2, (ya + yb) / 2, lab, 9.4, ORAN, ha='left')
+
+txt(nx, 43.8, 'The top state is pulled toward lower loss; each layer\'s mismatch $d_l$', 9)
+txt(nx, 40.8, 'transmits DOWN through the same weights, and the stack re-settles.', 9)
+txt(nx, 37.2, r'($J^{\top}$ = the transpose read a bidirectional physical device provides)', 8.6, GRAY)
+
+# ======================== the update ========================
+box(2, 18.5, 96, 15.0, fc=CREAM, ec=CREME, lw=1.2)
+txt(4, 30.9, 'The update — a difference measurement between the two settled states', 11, w='bold', ha='left')
+txt(50, 27.1, r'$\hat{g}\ =\ \left[\ \partial_\theta E(z^{\beta})\ -\ \partial_\theta E(z^{0})\ \right]\,/\,\beta$'
+              r'$\qquad\qquad(\partial_\theta E(z^0)\equiv 0\ \mathrm{here,\ since}\ E=0)$', 11)
+txt(50, 23.4, r'per layer:  $\Delta\theta_l\ \propto\ \langle\ d_l\ ,\ \partial f_l(z_{l-1})/\partial\theta_l\ \rangle\ /\ \beta$', 10)
+txt(50, 20.4, r'Each layer updates from its own boundary mismatch — no global backward graph, no global tape, no loss'
+              r' derivatives except the top nudge.', 8.6)
+
+fig.savefig('/home/yurenh2/ept/assets/fig_primer_phases.pdf')
+fig.savefig('/home/yurenh2/ept/assets/fig_primer_phases.png', dpi=185)
+fig.savefig('/home/yurenh2/ept/assets/fig_primer_phases.svg')
+print('saved fig_primer_phases.{pdf,png,svg}')