Fock-PARFLM v2.1 Anisotropic Gaussian V_theta + Fock Regularisation — Gamma Sweep with Geodesic Residual Analysis (OpenWebText, d=768)

This repository holds eight short (3,000-step) training runs, one per candidate damping coefficient γ{0.05,0.10,0.15,0.20,0.25,0.30,0.40,0.50}\gamma \in \{0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.40, 0.50\}, of the depth-conditioned anisotropic Gaussian VθV_\theta with Fock-coupling regularisation architecture, scaled up to d=768, L=16 and trained on OpenWebText. This is not a final trained model — it is the diagnostic sweep used to pick the damping coefficient for a subsequent full 100,000-step training run at this scale. Each of the 8 checkpoints is included in full.

Alongside the perplexity sweep, every checkpoint is also scored with the damped-geodesic residual Rˉ(γ)\bar{R}(\gamma) — a closed-form diagnostic (no additional training, no autodiff through a learned metric) that measures how closely each model's own hidden-state trajectory follows a geodesic of the Riemannian (Jacobi) metric induced by its own learned potential. The headline result:

Both the perplexity minimum and the geodesic-residual minimum land at γ=0.050\gamma = 0.050 — the smallest candidate tested, i.e. a boundary optimum rather than the interior minimum seen at d=384. This is also an exact, zero-parameter match to the two-regime closed-form damping predictor's high-\(d\) anchor prediction (\(\gamma^\ast_{\text{pred}} = 0.050\)) — the first time this predictor has been confirmed on a bounded anisotropic-Gaussian VθV_\theta at d768d \geq 768, at a depth (\(L=16\)) the original MLP-\(V_\theta\) d=768 sweep never used. See Coincidence, Boundary, and an Exact Predictor Match.

Based on this sweep, a full 100,000-step run at γ=0.05\gamma = 0.05 is expected to follow the same launch pattern as the d=384 run (currently in progress at γ=0.10\gamma=0.10); as of this card's creation the d=768 full run has not yet been launched.

This model is from the Semantic Simulation framework.

Table of Contents

When to Use This Repository

Use this repository if you want to:

  • Reproduce or extend the gamma-selection methodology for the anisotropic-Gaussian + Fock-reg Fock-PARFLM line at d=768, L=16 on OpenWebText, including the geodesic-residual diagnostic.
  • Study the non-monotonic PPL-vs-gamma wiggle that this width shares with the d=1024 sibling sweep but that no MLP-\(V_\theta\) sweep at comparable widths shows.
  • Compare geodesic fidelity across damping regimes on a bounded, analytically-differentiable potential — the closed-form Jacobi-metric machinery here is structurally unavailable to attention-based or MLP-potential architectures.

Do not use this repository if you want a well-trained OpenWebText language model: every checkpoint here has seen only 3,000 steps (~24.6M tokens at effective batch 8 x block 512) and none is intended to produce fluent text. For a fully trained OpenWebText-scale Fock-PARFLM checkpoint, see semsimula-fock-parflm-depthcond-vtheta-openwebtext (27.23 PPL, isotropic Gaussian, d=384, 250K steps) — no full-length d=768 run in this line exists yet.

Architecture

Identical Fock-PARFLM v2.1 scaffold to the d=384 gamma-sweep sibling, scaled up to d=768 and, specific to this width, given explicit force bounding for numerical stability:

Input tokens x_1, ..., x_T
       |
   Untied token embedding E[x] + learned positional P[t]
       |
   For each of L=16 damped-Euler integration steps (shared force field):
       |
       +-- K=5 causal-EMA context channels:
       |     xi^(m)_t = causal_ema(h, alpha_m)      [horizons ~2 .. ~200 tokens]
       |
       +-- Depth-conditioned multi-context V_theta (Anisotropic Gaussian, force-bounded):
       |     xi_g^(m) = xi^(m) + e_g^(m)                    [per-layer depth code]
       |     diff_k^m = h - mu_k^m(xi_g^(m))
       |     V_m = -sum_k w_k^m exp(-0.5[a_k^m . diff_k^{m2} + ||B_k^{mT} diff_k^m||^2])
       |     V_theta = sum_m V_m(xi_g^(m), h)               [5 contexts, 40 wells total]
       |     f_theta = clamp(-analytical_grad_h V_theta, max_norm=2/sqrt(768))
       |
       +-- Sparse pairwise V_phi (structural-competitive, 4 heads):
       |     top-k=16 past tokens per query (Gumbel routing)
       |     f_phi = -grad_h V_phi(h_t, h_s)                [autograd, sparse]
       |
       +-- Fock register pool (v2, 32 registers):
       |     M=32 virtual registers, Q/K/V creation gates, d_k=64
       |     LIFO stack discipline, per-register tau/keys, ortho init
       |     register repulsion (Gram penalty, lambda=0.05)
       |     reverse channel (per-layer, stabilised, pre-LN, soft-norm, warmup 4000)
       |     prefix-causal (leak-free by construction)
       |     f_fock = creation + destruction + exchange forces
       |
       +-- Total force: f = clamp(f_theta + f_phi + f_fock, max_norm=2/sqrt(768))
       |
       +-- Damped Euler step: v += dt*f/m; v /= (1 + dt*gamma); h += dt*v
       |
       +-- LayerNorm(h)
       |
   Logits = h @ W_out^T + b_out                              [UNTIED W_out]

Auxiliary training-only loss term (not part of the forward pass above):
   L_fock_coupling = -lambda_fock * sum_k log(alpha_k + eps)   [log-barrier on xi coupling]
Parameter Value
Hidden dim (d) 768
Layers (L) 16
Max sequence length 1024 (trained at block 512)
Vocab (GPT-2 BPE) 50257
V_theta kind Depth-conditioned multi-context anisotropic Gaussian (bounded mixture)
V_theta contexts (n_ctx) 5 (one bank per xi channel)
Wells per context (K) 8
Total attractors 40
Anisotropic rank (r) 4 — low-rank factor B_k in R^(768x4) per well
Precision init / cap a_k init at -log(768) (log-precision), capped at 2/768
Force bounding (d768-specific) VθV_\theta's own gradient norm and the model-level total force are both clamped to 2/7680.07222/\sqrt{768} \approx 0.0722 — not present in the d=384 sweep, added for stability at this width
Depth codes per-layer additive shift, shape (L=16, n_ctx=5, d=768), init std 0.02
Xi channels (K_xi) 5 (alpha inits 0.50, 0.75, 0.95, 0.99, 0.995)
Fock-coupling regulariser log-barrier on alpha_k, lambda=0.005, eps=1e-6 (see the TinyStories anchor for the full derivation)
V_phi kind structural_competitive
V_phi heads / d_type / d_angle 4 / 32 / 16
Top-k (sparse routing) 16
Fock version v2
Registers (M) 32
Register d_k 64
Stack discipline LIFO
Reverse channel Yes — per-layer, stabilised, pre-LN, soft-norm, 4,000-step warmup
Register repulsion Gram penalty, lambda=0.05
Embeddings Untied (separate W_out)
Mass model logfreq (frozen OpenWebText surprisal lookup)
lambda_V (V_theta regularisation) 0.01
Prefix-causal registers Yes — every checkpoint trained natively leak-free from step 0
Total parameters 225,354,011
V_theta parameters 141,834,280 (63% of total — the low-rank correction BkRd×rB_k \in \mathbb{R}^{d \times r} scales with dd, so widening from d=384 to d=768 roughly quadruples VθV_\theta's share of the model)

The analytical form of VθV_\theta — the diagonal-plus-rank-4 precision Σk1=diag(ak)+BkBk\Sigma_k^{-1} = \mathrm{diag}(a_k) + B_k B_k^\top, the depth-conditioning mechanism, and the closed-form bounded gradient — is unchanged from the TinyStories anchor and the d=384 sibling; only dd changes, plus the explicit force-norm clamp described above.

The Gamma Sweep

Eight candidate damping coefficients γ{0.05,0.10,0.15,0.20,0.25,0.30,0.40,0.50}\gamma \in \{0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.40, 0.50\} were each trained from scratch for 3,000 steps (WSD schedule, peak LR 3e-4, effective batch 8, up to 1B-token training pool), then scored on a held-out 2M-token OpenWebText validation slice. This protocol mirrors the d=384 sweep and is designed to be cheap: 8 x 3,000 steps rather than 8 x 100,000. The batch/grad-accum split (2x4 here vs. 2x8 at d=384) and the tighter gradient-clip ceilings (0.5 global / 0.2 for V_phi, vs. 1.0 / 0.3 at d=384) are both d768-specific stability adjustments.

The Geodesic Residual Diagnostic

Fock-PARFLM's scalar potential VθV_\theta is a closed-form Gaussian mixture with an analytical gradient, which makes a diagnostic available here that is structurally unavailable to attention-based or MLP-potential architectures: at fixed energy EE, Hamiltonian trajectories are geodesics of the Jacobi metric gijJ(x)=2(EV(x))δijg^J_{ij}(x) = 2(E - V(x))\delta_{ij}, a conformally flat metric whose Christoffel symbols are closed-form functions of Vθ\nabla V_\theta — no learned metric, no autodiff through a metric, no boundary-value solve.

For a trajectory with position stream xx_\ell, velocity stream vv_\ell, and measured acceleration aa_\ell (the discrete second difference of xx_\ell, consistent with the model's Velocity-Verlet-style integrator), the per-layer damped-geodesic residual is

R=a+Γ(v,v)+γva+ε,Γ(v,v)k=Γijkvivj, R_\ell = \frac{\big\lVert a_\ell + \Gamma(v_\ell, v_\ell) + \gamma v_\ell \big\rVert}{\lVert a_\ell \rVert + \varepsilon}, \qquad \Gamma(v,v)^k = \Gamma^k_{ij} v^i v^j,

where Γ\Gamma is computed in closed form from VθV_\theta's analytical gradient. R0R_\ell \approx 0 means the trajectory is a damped geodesic of the metric induced by the model's own learned potential — this is not a pure-conservation claim (the explicit γv\gamma v_\ell damping term is included), only that the dynamics satisfy the damped geodesic equation with the architecture's own damping coefficient. Averaging over layers and 10 fixed validation batches (seed 42) gives Rˉ(γtrain)\bar{R}(\gamma_{\text{train}}), evaluated at γeval=γtrain\gamma_{\text{eval}} = \gamma_{\text{train}} for each retained checkpoint — the diagonal overlay against PPL(γtrain)\mathrm{PPL}(\gamma_{\text{train}}).

A second, closed-form quantity — the recovered intrinsic damping γgeo\gamma_{\text{geo}} — is the least-squares row minimiser "the damping value that best explains this specific trajectory," independent of what γ\gamma the model was actually trained with:

γgeo=a+Γ(v,v), vv2. \gamma_{\text{geo}} = -\frac{\big\langle a_\ell + \Gamma(v_\ell, v_\ell),\ v_\ell \big\rangle}{\lVert v_\ell \rVert^{2}}.

Full derivation, practical mitigations (turning-point exclusion, reference-energy convention, integrator staggering), and validation controls (vanilla-baseline, shuffled-\(\Gamma\), and random-direction nulls) are in the companion note Geodesic_Preservation_Experiment.md.

Results: A Boundary Optimum at Gamma 0.05

γ\gamma PPL Rˉ\bar{R} γgeo\gamma_{\text{geo}} Excluded frac
0.050 326.97 ← PPL min 1.2813Rˉ\bar{R} min 0.9829 0%
0.100 350.70 1.9648 0.9828 0%
0.150 340.25 1.5159 0.9827 0%
0.200 368.62 1.7544 0.9795 0%
0.250 362.39 2.9092 0.9840 0%
0.300 362.44 1.4901 0.9735 0%
0.400 393.47 3.5790 0.9848 0%
0.500 364.94 2.6750 0.9781 0%

PPL vs geodesic residual overlay for d=768 aniso-Gaussian + fock-reg gamma sweep

The minima coincide, at the boundary of the swept range. Both PPL and Rˉ\bar{R} bottom out at γ=0.050\gamma = 0.050, the smallest gamma tested — unlike the d=384 sweep, where the joint minimum sat at an interior point (\(0.100\)) with worse candidates on both sides. γgeo\gamma_{\text{geo}} also shows the tightest cross-gamma clustering of any sweep in this family to date: mean 0.98100.9810, std 0.00350.0035 — essentially flat across a full order-of-magnitude range of nominal training γ\gamma (0.05 to 0.50), the same "intrinsic preferred geometry" signature documented at every other scale, but here with less than half the spread seen at d=384.

The per-layer residual heatmap below shows where in the network the departures from geodesic behaviour concentrate at each damping level — notice the bright band across nearly every layer at γ=0.40\gamma=0.40, the sweep's worst PPL candidate, and the uniformly dark (near-geodesic) row at γ=0.05\gamma=0.05:

Per-layer geodesic residual heatmap for d=768 aniso-Gaussian + fock-reg gamma sweep

The recovered intrinsic damping is visually almost a flat line across the entire swept range:

Recovered intrinsic damping vs training gamma for d=768 aniso-Gaussian + fock-reg gamma sweep

The Non-Monotonic Wiggle Past the Minimum

Unlike the original MLP-\(V_\theta\) d=768 sweep (a clean, monotonic PPL increase from γ=0.05\gamma=0.05 to 0.500.50; see Fock-PARFLM_Scale-Up_Gamma_Sweep_Results_and_Damping_Regime_Analysis.md), this anisotropic-Gaussian sweep is non-monotonic past its minimum: PPL rises from 326.97 (\(\gamma=0.05\)) to a local peak at γ=0.20\gamma=0.20 (368.62), dips back down at γ=0.25\gamma=0.25-\(0.30\) (362.39, 362.44), rises again to the sweep's worst point at γ=0.40\gamma=0.40 (393.47), then partially recovers at γ=0.50\gamma=0.50 (364.94).

The overall ranking is not in doubt — γ=0.05\gamma=0.05 leads its nearest competitor (\(\gamma=0.15\), 340.25 PPL) by 13.28 PPL, about 4% — but the wiggle itself is a genuine feature of the aniso-Gaussian + Fock-reg configuration that no MLP-\(V_\theta\) sweep at comparable widths shows. A companion sweep at d=1024 (not yet uploaded to this collection) shows the same wiggle shape, with a local peak in the same \gamma \approx 0.20\)-\\(0.40 range before a partial recovery at 0.40-0.50 — a weak but real argument against pure single-run noise, since independent per-candidate noise would not obviously line up at matching γ\gamma values across two different widths. Two candidate explanations remain open (not mutually exclusive): (1) single-seed optimisation noise riding on a genuinely flat or slowly-varying underlying PPL surface, or (2) a structural interaction between the anisotropic precision matrices (or the reverse channel) and mid-range explicit friction. Disentangling them would require a 2-3 seed rerun of one or two candidates (e.g. γ=0.30\gamma=0.30) — not yet done. See Determining_optimal_gamma_for_Fock-PARFLM.md §14.5 for the full cross-scale discussion.

Coincidence, Boundary, and an Exact Predictor Match

The two-regime closed-form damping predictor, calibrated on the original (MLP) VθV_\theta family, gives at d=768d=768, L=16L=16, mˉ=1.4\bar{m}=1.4 (using the high-\(d\) regime constant ρhi=0.565\rho_{\text{hi}} = 0.565):

γpred=1.416ln(1/0.565)=0.0875×0.571=0.050 \gamma^{\ast}_{\text{pred}} = \frac{1.4}{16}\ln(1/0.565) = 0.0875 \times 0.571 = 0.050

Empirical γ=0.050\gamma^{\ast} = 0.050. Exact match, zero error. This resolves an open question left by the d=384 sweep — whether the aniso-Gaussian family's crossover, once past d=384d=384, matches the high-\(d\) anchor exactly (as the MLP-\(V_\theta\) family does) or retains a residual offset. It matches exactly, and at a depth (\(L=16\)) the original MLP d=768d=768 sweep never tested (that sweep used L=12L=12, where the depth-only formula overshoots by 33% — a known, pre-existing discrepancy unrelated to this architecture). Combined with the same exact match found in the d=1024 companion sweep, this is the strongest evidence to date that ρhi=0.565\rho_{\text{hi}}=0.565 is a genuine architecture-family invariant at d768d \gtrsim 768, not an artefact of the MLP VθV_\theta or of the specific depths swept when the constant was first calibrated.

Sweep dd LL VθV_\theta γpred\gamma^\ast_{\text{pred}} γempirical\gamma^\ast_{\text{empirical}} Match
Original MLP d=768 sweep 768 12 MLP 0.067 0.05 +33% (known L=12L=12 depth-formula overshoot)
This sweep 768 16 aniso-Gaussian + fock-reg 0.050 0.050 Exact
d=1024 companion (not yet uploaded) 1024 16 aniso-Gaussian + fock-reg 0.050 0.050 Exact

Comparison to the d=384 Sibling

Sweep γPPL\gamma^\ast_{\text{PPL}} γRˉ\gamma^\ast_{\bar{R}} Coincidence? Optimum shape Margin vs. runner-up
d=384, L=16 0.100 0.100 Yes — gap 0 Interior minimum large
d=768, L=16 (this sweep) 0.050 0.050 Yes — gap 0 Boundary minimum ~4%, modest

Both widths show coinciding PPL and geodesic-residual minima — extending the pattern first seen at d=384 to a second, larger width — but the shape of the optimum differs: d=384's winner sits strictly between two worse neighbours (a genuine interior bowl, only slightly undermined by the γ=0.20\gamma=0.20 divergence outlier there), while d=768's winner is the smallest gamma tested, with PPL and Rˉ\bar{R} both rising (non-monotonically) as gamma increases from there. The γgeo\gamma_{\text{geo}} clustering is also tighter at d=768 (std 0.0035 vs. a wider spread at d=384, driven partly by that sweep's γ=0.20\gamma=0.20 outlier) — consistent with a model that has, if anything, an even more uniform intrinsic damping preference at this width.

Caveats: Short-Sweep Reliability

This is a 3,000-step, single-seed measurement per gamma, and the family has one documented case where a short-sweep ranking reversed at full training length: the d=256 TinyStories aniso-Gaussian sweep favoured γ=0.150\gamma=0.150 at 3K steps, but the full 20K-step run favoured γ=0.300\gamma=0.300 instead. Two considerations specific to this sweep are worth weighing before trusting γ=0.05\gamma=0.05 at a full 100K-step horizon:

  • The margin between γ=0.05\gamma=0.05 and its nearest competitor (\(\gamma=0.15\)) is real but modest — about 4%, right at the edge of the family's informal "flat bowl, ranking unreliable" threshold (5%) from the earlier d=256 reversal analysis. The d=1024 companion sweep's margin (10-11%) is comfortably wider.
  • The non-monotonic wiggle documented above shows this configuration is not perfectly smooth in gamma, so the training log for a full run should still be watched for instability signatures analogous to the d=384 sweep's γ=0.20\gamma=0.20 divergence-and-partial-recovery excursion, as an early-warning check.

Two considerations nonetheless favour trusting this sweep's recommendation more than a typical modest-margin case: (a) unlike the flat interior bowls at d384d \leq 384 where the documented reversal actually occurred, this is a boundary optimum with γgeo\gamma_{\text{geo}} essentially flat across the whole range — there is no competing interior basin the sweep could be misranking within, only a preference for less explicit friction that a longer horizon is unlikely to overturn; and (b) the predictor's independent, zero-parameter prediction lands on the exact same value (above). Recommendation: γ=0.05\gamma=0.05 for the d=768, L=16 aniso-Gaussian full run.

How to Get Started

import math, torch, sys
sys.path.insert(0, "multixi")
sys.path.insert(0, "parf")
sys.path.insert(0, "energetic_minima")
sys.path.insert(0, "sarf_mass_variant")

from parf.model_fock_parf_multixi import FockMultiXiPARFLM, FockMultiXiPARFConfig
from parf.model_aniso_gaussian_vtheta import AnisotropicDepthConditionedGaussianVTheta, install_aniso_depth_routing
from huggingface_hub import hf_hub_download

REPO = "dimitarpg13/semsimula-fock-parflm-anisogaussian-vtheta-owt-d768-gammasweep"
GAMMA = "0.050"  # the recommended candidate; also available: 0.100, 0.150, 0.200, 0.250, 0.300, 0.400, 0.500

logfreq_path = hf_hub_download(repo_id=REPO, filename="results/logfreq_surprisal_openwebtext.npy")
FORCE_MAX = 2.0 / math.sqrt(768)

config = FockMultiXiPARFConfig(
    vocab_size=50257, d=768, max_len=1024, L=16,
    v_hidden=1024, v_depth=3, dt=1.0,
    mass_mode="logfreq", logfreq_path=logfreq_path, logfreq_init_alpha=0.1,
    init_gamma=1.0, fixed_gamma=float(GAMMA),
    causal_force=True, ln_after_step=True,
    xi_channels=5, xi_alpha_inits=[0.50, 0.75, 0.95, 0.99, 0.995],
    xi_learnable=True, xi_alpha_init_mode="explicit",
    fock_version="v2", n_registers=32,
    reverse_channel=True, reverse_channel_stable=True, reverse_channel_pre_ln=True,
    reverse_channel_soft_norm=True, reverse_channel_warmup_steps=4000, reverse_channel_per_layer=True,
    register_repulsion=True, register_repulsion_coeff=0.05,
    prefix_causal_registers=True,
    v_phi_kind="structural_competitive", v_phi_n_heads=4, v_phi_d_type=32, v_phi_d_angle=16,
    v_phi_eps=0.1, v_phi_phi_hidden=128, v_phi_theta_hidden=128, v_phi_mlp_hidden=128,
    top_k=16,
    use_output_bias=True, tie_embeddings=False,
    score_head_hidden=32,
    gumbel_tau_init=1.0, gumbel_tau_min=0.3, gumbel_noise=True,
    use_gathered_v_phi=True,
    use_layer_checkpoint=True,
    ln_before_distance=True, per_layer_v_phi_scale=True,
    register_salience_decay=0.5, register_salience_threshold=0.005,
    creation_gate_hidden=64, stack_discipline=True,
    d_k=64, tau_create_init=8.0,
    per_register_tau=True, per_register_keys=True,
    ortho_register_init=True,
    force_clamp_max=FORCE_MAX,
)
model = FockMultiXiPARFLM(config)

model.V_theta = AnisotropicDepthConditionedGaussianVTheta(
    d=768, K=8, n_ctx=5, n_layers=16, rank=4,
    w_scale=1.0,
    init_log_precision=-math.log(768),
    precision_max=2.0 / 768,
    force_norm_max=FORCE_MAX,
    code_init_std=0.02,
)
install_aniso_depth_routing(model)

ckpt_path = hf_hub_download(repo_id=REPO, filename=f"checkpoints/gamma_{GAMMA}/ckpt_best.pt")
state = torch.load(ckpt_path, map_location="cpu", weights_only=False)
model.load_state_dict(state["model_state_dict"])
model.eval()

print(f"Parameters: {sum(p.numel() for p in model.parameters()):,}")            # 225,354,011
print(f"gamma={state['gamma']}  step={state['step']:,}  val_ppl={state['val_ppl']:.2f}")

Available Artifacts

Path Description
checkpoints/gamma_0.050/ckpt_best.pt ... checkpoints/gamma_0.500/ckpt_best.pt All 8 gamma-sweep checkpoints (step 3,000 each), each a dict with model_state_dict, optimizer_state_dict, step, val_loss, val_ppl, gamma, v_theta_variant, aniso_rank, lambda_fock_reg
checkpoints/gamma_*/training_log.jsonl Per-500-step training metrics and the step-2,000 causal_probe event, one file per gamma
sweep_summary.json Sweep-level summary (best PPL per gamma, wall-clock)
results/geodesic_results.json Full per-gamma geodesic residual data: Rˉ\bar{R}, γgeo\gamma_{\text{geo}}, excluded fraction, and all 15 per-layer residuals
results/geodesic_overlay_aniso_gaussian_d768.png PPL vs. geodesic residual dual-axis overlay
results/geodesic_per_layer_aniso_gaussian_d768.png Per-layer, per-gamma geodesic residual heatmap
results/gamma_geo_recovery_aniso_gaussian_d768.png Recovered intrinsic damping γgeo\gamma_{\text{geo}} vs. training gamma
results/logfreq_surprisal_openwebtext.npy Frozen per-token log-frequency (surprisal) lookup used by the logfreq mass model
model_aniso_gaussian_vtheta.py Anisotropic Gaussian V_theta classes + install_aniso_depth_routing (identical file to the TinyStories anchor's and the d=384 sibling's)
config.json Full sweep configuration, per-gamma results table, and predictor comparison

Training Details

Training Data

OpenWebText, tokenized with GPT-2 BPE (vocab 50257). Each candidate trains on up to 1B tokens (early stopped at 3,000 steps, effective batch 8, block 512 -> ~12.3M tokens actually consumed) and is evaluated on a held-out 2M-token validation slice with no train/val overlap.

Training Procedure (per gamma candidate)

Hyperparameter Value
Optimizer AdamW (betas 0.9/0.95, weight decay 0.01)
LR schedule WSD (warmup 0-150, stable 150-1950, decay 1950-3000)
Peak learning rate 3e-4
Batch size 2 x grad-accum 4 (effective 8)
Block size 512
Steps 3,000
Gradient clipping per-group (global 0.5; V_phi 0.2 — tighter than d=384's 1.0/0.3, a d768-specific stability adjustment)
Force clamp (model-level and V_theta-level) 2/7680.07222/\sqrt{768} \approx 0.0722
lambda_V (V_theta regularisation) 0.01
lambda_fock (coupling regulariser) 0.005
Seed 0
Hardware 1x NVIDIA H100/A100 (Google Colab)

Causal-Leak Verification

All 8 checkpoints were trained natively with prefix_causal_registers=True from step 0. The bit-exact future-perturbation causal probe passed with max_delta=0.0 at step 2,000 for every one of the 8 gamma candidates.

Training Script

notebooks/conservative_arch/scaleup/colab_fock_gamma_sweep_geodesic_aniso_gaussian_fockreg_d768.ipynb (companion repo) — self-contained Colab notebook that runs the 8-candidate sweep, the geodesic residual analysis, and produces the overlay/heatmap/recovery figures in one pass, requiring no additional training beyond the sweep itself.

Evaluation Results

OpenWebText Validation Perplexity (3,000-step sweep candidates)

γ\gamma PPL Rank
0.050 326.97 1st
0.150 340.25 2nd
0.300 362.44 3rd
0.250 362.39 4th
0.500 364.94 5th
0.100 350.70 6th
0.200 368.62 7th
0.400 393.47 8th

These PPL values are from 3,000-step short-sweep candidates and are not comparable to the fully trained OpenWebText checkpoints elsewhere in this family (e.g. 27.23 PPL after 250K steps for the isotropic d=384 flagship). They exist solely to rank candidate damping coefficients. Note the ranking is not simply increasing with γ\gamma; see The Non-Monotonic Wiggle Past the Minimum.

See Results: A Boundary Optimum at Gamma 0.05 for the combined PPL / geodesic-residual table.

SPLM Family Overview

This model is part of the Semantic Simulation SPLM family:

Model Design Corpus PPL HuggingFace
Multi-Xi SPLM (MLP) Pure scalar potential TinyStories 11.51 semsimula-splm-multixi
Multi-Xi PARFLM (MLP) Scalar + pairwise forces TinyStories 12.06 semsimula-parflm-multixi
Fock-PARFLM v2.1 (MLP) PARFLM + Fock registers TinyStories 9.70 semsimula-fock-parflm
Fock-PARFLM v2.1 (SQ3) Structured + pairwise + Fock TinyStories 10.90 semsimula-fock-parflm-structured-vtheta
Fock-PARFLM v2.1 (depth-cond. isotropic Gaussian) Bounded multi-context + pairwise + Fock TinyStories 16.33 semsimula-fock-parflm-depthcond-vtheta
Fock-PARFLM v2.1 (depth-cond. anisotropic Gaussian + fock-reg) Bounded, ellipsoidal multi-context + pairwise + Fock TinyStories 9.04 semsimula-fock-parflm-anisogaussian-vtheta
Fock-PARFLM v2.1 (aniso-Gaussian + fock-reg, first-order/Fock-G1) Same as above, gradient-flow integrator TinyStories 8.95 semsimula-fock-parflm-anisogaussian-vtheta-fock-g1
Fock-PARFLM v2.1 (depth-cond. Gaussian, OpenWebText scale) Bounded multi-context + pairwise + Fock, d=384 L=16 OpenWebText 27.23 semsimula-fock-parflm-depthcond-vtheta-openwebtext
Fock-PARFLM v2.1 (aniso-Gaussian + fock-reg, gamma sweep, d=384) Bounded, ellipsoidal multi-context + pairwise + Fock — 8-way gamma sweep + geodesic analysis OpenWebText 278.27 (best of 8, 3K-step sweep, not a final model) semsimula-fock-parflm-anisogaussian-vtheta-owt-d384-gammasweep
Fock-PARFLM v2.1 (aniso-Gaussian + fock-reg, gamma sweep, d=768) Bounded, ellipsoidal multi-context + pairwise + Fock — 8-way gamma sweep + geodesic analysis OpenWebText 326.97 (best of 8, 3K-step sweep, not a final model) this repository
Fock-Attention Fock + attention TinyStories 9.42 semsimula-fock-attention
Hybrid SPLM+Attn Attention + SPLM refinement TinyStories 8.50 semsimula-hybrid-splm

Collection: Semantic Simulation SPLM Model Family

Bias, Risks, and Limitations

  • Not a final trained model. Every checkpoint in this repository has been trained for only 3,000 steps — a gamma-selection diagnostic, not a language model intended for generation or downstream use. Do not compare its PPL to fully trained checkpoints elsewhere in this family.
  • Single-seed sweep. Each gamma candidate is one run; no seed-variance estimate is available. The margin between γ=0.05\gamma=0.05 and its nearest competitor (~4%) is real but modest; see Caveats: Short-Sweep Reliability.
  • Short-horizon ranking can reverse. The family has one documented case (d=256 TinyStories) where the short-sweep-optimal gamma differed from the full-run-optimal gamma. The γ=0.05\gamma=0.05 recommendation here carries some of the same risk, mitigated by the boundary-optimum shape and the exact predictor match; see the caveats section.
  • Non-monotonic PPL-vs-gamma wiggle, shared with the d=1024 companion sweep, is not yet explained (single-seed noise vs. a structural property of this VθV_\theta configuration); see above.
  • OpenWebText only, English only. No instruction tuning, no RLHF/DPO, no safety filtering.
  • Geodesic residual is a diagnostic, not a training objective. The model was trained to minimise cross-entropy; the near-geodesic behaviour at γ=0.05\gamma=0.05 is an emergent structural property, not something the loss function directly optimises for.
  • Very large VθV_\theta hypernetwork. At 141.8M parameters, VθV_\theta alone is 63% of the 225M-parameter total — a substantially larger share than the d=384 sibling's 46%, driven by the low-rank correction BkRd×rB_k \in \mathbb{R}^{d \times r} scaling with dd.
  • No causal-leak issue. All 8 checkpoints were trained natively with prefix_causal_registers=True; see Causal-Leak Verification.

Citation

@misc{Gueorguiev2026SemSim,
  author    = {Gueorguiev, Dimitar P.},
  title     = {Semantic Simulation: A Prescriptive Lagrangian Framework
               for Efficient Semantic Inference --- A Conservative-by-
               Construction Language Model and the Shared-Potential
               Separator, with a Correspondence to Joint Embedding
               Predictive Architectures},
  year      = {2026},
  publisher = {Zenodo},
  doi       = {10.5281/zenodo.19712427},
  url       = {https://doi.org/10.5281/zenodo.19712427},
  note      = {Companion code repository:
               \url{https://github.com/dimitarpg13/semsimula-paper}}
}

Environmental Impact

  • Hardware: 1x NVIDIA H100/A100 80GB (Google Colab)
  • Training: 8 x 3,000 steps = 24,000 total training steps across the sweep, plus inference-only geodesic residual analysis (10 validation batches x 8 checkpoints, no additional training)
  • Carbon footprint: small; a single-GPU research sweep, estimated on the order of a few kg CO2
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Dataset used to train dimitarpg13/semsimula-fock-parflm-anisogaussian-vtheta-owt-d768-gammasweep

Collection including dimitarpg13/semsimula-fock-parflm-anisogaussian-vtheta-owt-d768-gammasweep

Evaluation results

  • Validation Perplexity (gamma=0.05, best of 8 gamma-sweep candidates, 3,000-step short sweep — not a fully trained model) on OpenWebText
    validation set self-reported
    326.970