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Delete docs/v0.3.0-design.md and strip all references to it
The design doc and its followups doc are no longer needed as a live
reference now that the v0.3.0 redesign is implemented — comments and
docstrings across the codebase cited it extensively (file path, "design
doc §X.Y", "decision N", or bare "§X.Y" section numbers) as design
rationale. Removed docs/ and edited every citing comment/docstring to
drop the now-dangling reference while keeping the substantive
explanation next to it. CLAUDE.md's v0.3.0 roadmap bullet loses its
trailing pointer to the deleted file.

Verified: no remaining "docs/v0.3.0", "design doc", "decision N", or
"§N.N" references (repo-wide grep); ruff and ty clean; full test suite
on the heaviest-touched modules (network, sample, rollout, migration,
config, train) passes.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
2026-08-10 11:19:02 +02:00

1105 lines
36 KiB
Python

"""Frozen snapshot of `giant/model/network.py` as it stood at the v0.3.0
"step 1" commit (eb6dd27), i.e. the last commit before the step-2
composable-parts decomposition.
This is a deliberate verbatim copy, not an import of the live module — the
whole point is that this file's classes keep behaving exactly as v0.2 did
even after `giant/model/network.py` itself is rewritten, so
`tests/test_migration_v02_v03.py` has a stable "old" side to diff the new
`build_models`/`Stage1Model`/`Stage2OneShot` against (the bit-identical
acceptance test). Do not edit this file to track future
`network.py` changes — it exists specifically to stop tracking them.
"""
import inspect
import math
import re
from collections.abc import Sequence
import torch
import torch.nn as nn
import torch.nn.functional as F
from giant.constants import (
COND_DIM,
COND_DIM_BASE,
EMB_DIM,
K_MAX,
MATERIAL_PHYS_DIM,
PARTICLE_PHYS_DIM,
SEC_DIM,
X_DIM,
)
class SinusoidalEmbedding(nn.Module):
def __init__(self, dim: int) -> None:
super().__init__()
assert dim % 2 == 0, "dim must be even"
half = dim // 2
freqs = torch.exp(
-math.log(10000)
* torch.arange(half, dtype=torch.float32)
/ max(half - 1, 1)
)
self.register_buffer("freqs", freqs)
def forward(self, t: torch.Tensor) -> torch.Tensor:
t = t.reshape(-1, 1).float()
args = t * self.freqs.unsqueeze(0) # (B, half)
return torch.cat([args.sin(), args.cos()], dim=-1) # (B, dim)
class ConditionEncoder(nn.Module):
"""Fuses continuous conditioning with particle/material identity.
Two mutually exclusive ways to turn (pdg, material) identity into the
two `emb_dim`-wide vectors concatenated with the base continuous
conditioning before the fusion MLP:
- "embedding": a learned `nn.Embedding` lookup table per axis, indexed
by `cond_cat`'s dense training-vocab index. Memorizes the training
menu; the original Phase-2 design.
- "physical": a small MLP per axis, mapping the axis's raw physical
properties (already present in `cond_cont[:, COND_DIM_BASE:]` — see
giant.data.transforms.build_features) to an `emb_dim`-wide vector —
a drop-in replacement for the embedding lookup, computable for any
PDG code / material name rather than only ones seen in training.
Both modes produce the same `in_dim = COND_DIM_BASE + 2*emb_dim` for the
fusion MLP, so only how the two vectors are produced differs.
"""
def __init__(
self,
pdg_vocab: int,
mat_vocab: int,
cont_dim: int = COND_DIM,
emb_dim: int = 16,
out_dim: int = 128,
conditioning: str = "embedding",
) -> None:
super().__init__()
if conditioning not in ("embedding", "physical"):
raise ValueError(f"unknown conditioning mode {conditioning!r}")
self.conditioning = conditioning
if conditioning == "embedding":
self.pdg_emb = nn.Embedding(pdg_vocab, emb_dim)
self.mat_emb = nn.Embedding(mat_vocab, emb_dim)
else:
self.particle_mlp = nn.Sequential(
nn.Linear(PARTICLE_PHYS_DIM, emb_dim),
nn.SiLU(),
nn.Linear(emb_dim, emb_dim),
)
self.material_mlp = nn.Sequential(
nn.Linear(MATERIAL_PHYS_DIM, emb_dim),
nn.SiLU(),
nn.Linear(emb_dim, emb_dim),
)
in_dim = COND_DIM_BASE + 2 * emb_dim
self.mlp = nn.Sequential(
nn.Linear(in_dim, out_dim),
nn.SiLU(),
nn.Linear(out_dim, out_dim),
)
def forward(self, cond_cont: torch.Tensor, cond_cat: torch.Tensor) -> torch.Tensor:
if self.conditioning == "embedding":
pdg_e = self.pdg_emb(cond_cat[:, 0])
mat_e = self.mat_emb(cond_cat[:, 1])
else:
particle_phys = cond_cont[
:, COND_DIM_BASE : COND_DIM_BASE + PARTICLE_PHYS_DIM
]
material_phys = cond_cont[:, COND_DIM_BASE + PARTICLE_PHYS_DIM :]
pdg_e = self.particle_mlp(particle_phys)
mat_e = self.material_mlp(material_phys)
x = torch.cat([cond_cont[:, :COND_DIM_BASE], pdg_e, mat_e], dim=-1)
return self.mlp(x)
class ResBlock(nn.Module):
def __init__(self, dim: int, cond_dim: int, dropout: float = 0.1) -> None:
super().__init__()
self.norm = nn.LayerNorm(dim)
self.linear1 = nn.Linear(dim, dim)
self.cond_proj = nn.Linear(cond_dim, dim, bias=False)
self.act = nn.SiLU()
self.dropout = nn.Dropout(dropout)
self.linear2 = nn.Linear(dim, dim)
def forward(self, x: torch.Tensor, cond: torch.Tensor) -> torch.Tensor:
h = self.norm(x)
h = self.linear1(h) + self.cond_proj(cond)
h = self.act(h)
h = self.dropout(h)
h = self.linear2(h)
return x + h
class DenoisingMLP(nn.Module):
"""Stage-1 model: predicts the 9D primary post-step vector field + n_sec logits.
The n_sec head runs on the condition encoding only (no diffusion noise),
so it can be called at inference time independently via `predict_n_sec`.
"""
def __init__(
self,
pdg_vocab: int,
mat_vocab: int,
hidden_dim: int = 256,
n_blocks: int = 6,
emb_dim: int = 16,
time_dim: int = 64,
cond_out_dim: int = 128,
x_dim: int = X_DIM,
dropout: float = 0.1,
k_max: int = K_MAX,
conditioning: str = "embedding",
) -> None:
super().__init__()
self.time_emb = SinusoidalEmbedding(time_dim)
self.cond_enc = ConditionEncoder(
pdg_vocab=pdg_vocab,
mat_vocab=mat_vocab,
emb_dim=emb_dim,
out_dim=cond_out_dim,
conditioning=conditioning,
)
merged_cond_dim = time_dim + cond_out_dim
self.input_proj = nn.Linear(x_dim, hidden_dim)
self.blocks = nn.ModuleList(
[
ResBlock(hidden_dim, merged_cond_dim, dropout=dropout)
for _ in range(n_blocks)
]
)
self.out_proj = nn.Linear(hidden_dim, x_dim)
# Predicts n_sec as classification over {0, 1, ..., k_max}.
# Applied to the condition encoding (not the diffused latent).
self.n_sec_head = nn.Sequential(
nn.Linear(cond_out_dim, hidden_dim // 2),
nn.SiLU(),
nn.Linear(hidden_dim // 2, k_max + 1),
)
def forward(
self,
x_t: torch.Tensor,
t: torch.Tensor,
cond_cont: torch.Tensor,
cond_cat: torch.Tensor,
) -> torch.Tensor:
t_emb = self.time_emb(t) # (B, time_dim)
c_emb = self.cond_enc(cond_cont, cond_cat) # (B, cond_out_dim)
cond = torch.cat([t_emb, c_emb], dim=-1)
x = self.input_proj(x_t)
for block in self.blocks:
x = block(x, cond)
return self.out_proj(x)
def predict_n_sec(
self,
cond_cont: torch.Tensor,
cond_cat: torch.Tensor,
) -> torch.Tensor:
"""Return n_sec logits (B, K_MAX+1) from conditioning alone."""
c_emb = self.cond_enc(cond_cont, cond_cat)
return self.n_sec_head(c_emb)
class SecondaryConditionEncoder(nn.Module):
"""Encodes pre-step conditioning + Stage-1 output for the secondary decoder."""
def __init__(
self,
pdg_vocab: int,
mat_vocab: int,
emb_dim: int = 16,
cond_out_dim: int = 128,
stage1_dim: int = X_DIM,
stage1_proj_dim: int = 64,
out_dim: int = 128,
conditioning: str = "embedding",
) -> None:
super().__init__()
self.base = ConditionEncoder(
pdg_vocab=pdg_vocab,
mat_vocab=mat_vocab,
emb_dim=emb_dim,
out_dim=cond_out_dim,
conditioning=conditioning,
)
self.stage1_proj = nn.Linear(stage1_dim, stage1_proj_dim)
fused_dim = cond_out_dim + stage1_proj_dim
self.fuse = nn.Sequential(
nn.Linear(fused_dim, out_dim),
nn.SiLU(),
)
def forward(
self,
cond_cont: torch.Tensor,
cond_cat: torch.Tensor,
stage1_out: torch.Tensor,
) -> torch.Tensor:
base = self.base(cond_cont, cond_cat) # (B, cond_out_dim)
s1 = self.stage1_proj(stage1_out).tanh() # (B, stage1_proj_dim)
return self.fuse(torch.cat([base, s1], dim=-1)) # (B, out_dim)
class SecondaryDecoder(nn.Module):
"""Stage-2 model: predicts vector field over K_MAX secondary slots simultaneously.
Each slot encodes (stick_break_logit, local_dir_3D, log_mass, charge) for
one secondary ordered by descending energy — mass/charge are the
secondary's predicted physical identity, regressed directly against real
physics targets (see giant.data.transforms.encode_secondaries), used
as-is with no snapping to a discrete PDG code. Padded slots are masked
from loss.
"""
def __init__(
self,
pdg_vocab: int,
mat_vocab: int,
hidden_dim: int = 256,
n_blocks: int = 6,
emb_dim: int = 16,
time_dim: int = 64,
cond_out_dim: int = 128,
stage1_proj_dim: int = 64,
sec_dim: int = SEC_DIM,
dropout: float = 0.1,
conditioning: str = "embedding",
) -> None:
super().__init__()
self.time_emb = SinusoidalEmbedding(time_dim)
self.cond_enc = SecondaryConditionEncoder(
pdg_vocab=pdg_vocab,
mat_vocab=mat_vocab,
emb_dim=emb_dim,
cond_out_dim=cond_out_dim,
stage1_proj_dim=stage1_proj_dim,
out_dim=cond_out_dim,
conditioning=conditioning,
)
merged_cond_dim = time_dim + cond_out_dim
self.input_proj = nn.Linear(sec_dim, hidden_dim)
self.blocks = nn.ModuleList(
[
ResBlock(hidden_dim, merged_cond_dim, dropout=dropout)
for _ in range(n_blocks)
]
)
self.out_proj = nn.Linear(hidden_dim, sec_dim)
def forward(
self,
x_t: torch.Tensor,
t: torch.Tensor,
cond_cont: torch.Tensor,
cond_cat: torch.Tensor,
stage1_out: torch.Tensor,
) -> torch.Tensor:
t_emb = self.time_emb(t)
c_emb = self.cond_enc(cond_cont, cond_cat, stage1_out)
cond = torch.cat([t_emb, c_emb], dim=-1)
x = self.input_proj(x_t)
for block in self.blocks:
x = block(x, cond)
return self.out_proj(x)
class WGANGenerator(nn.Module):
"""Stage-1 WGAN-GP generator: single forward pass, no diffusion/flow time.
Same `ConditionEncoder` + `ResBlock` trunk as `DenoisingMLP`, but the
input is a noise vector `z` (not a diffused/interpolated `x_t`) and the
ResBlocks condition on the condition encoding alone (no time embedding to
concatenate) — see `giant/model/wgan.py` for the adversarial losses, and
`giant.sample.sample_wgan` for single-pass sampling.
"""
def __init__(
self,
pdg_vocab: int,
mat_vocab: int,
hidden_dim: int = 256,
n_blocks: int = 6,
emb_dim: int = 16,
cond_out_dim: int = 128,
x_dim: int = X_DIM,
noise_dim: int = 64,
dropout: float = 0.1,
k_max: int = K_MAX,
conditioning: str = "embedding",
) -> None:
super().__init__()
self.noise_dim = noise_dim
self.cond_enc = ConditionEncoder(
pdg_vocab=pdg_vocab,
mat_vocab=mat_vocab,
emb_dim=emb_dim,
out_dim=cond_out_dim,
conditioning=conditioning,
)
self.input_proj = nn.Linear(noise_dim, hidden_dim)
self.blocks = nn.ModuleList(
[
ResBlock(hidden_dim, cond_out_dim, dropout=dropout)
for _ in range(n_blocks)
]
)
self.out_proj = nn.Linear(hidden_dim, x_dim)
self.n_sec_head = nn.Sequential(
nn.Linear(cond_out_dim, hidden_dim // 2),
nn.SiLU(),
nn.Linear(hidden_dim // 2, k_max + 1),
)
def forward(
self,
z: torch.Tensor,
cond_cont: torch.Tensor,
cond_cat: torch.Tensor,
) -> torch.Tensor:
cond = self.cond_enc(cond_cont, cond_cat)
x = self.input_proj(z)
for block in self.blocks:
x = block(x, cond)
return self.out_proj(x)
def predict_n_sec(
self,
cond_cont: torch.Tensor,
cond_cat: torch.Tensor,
) -> torch.Tensor:
"""Return n_sec logits (B, K_MAX+1) from conditioning alone."""
c_emb = self.cond_enc(cond_cont, cond_cat)
return self.n_sec_head(c_emb)
class Critic(nn.Module):
"""Stage-1 WGAN-GP critic: scalar realism score, own `ConditionEncoder`.
Kept structurally parallel to `WGANGenerator` (own condition encoder —
separate weights from the generator's, standard GAN practice) but has no
n_sec head: n_sec is never adversarial, it stays a plain classifier on
the generator side.
"""
def __init__(
self,
pdg_vocab: int,
mat_vocab: int,
hidden_dim: int = 256,
n_blocks: int = 6,
emb_dim: int = 16,
cond_out_dim: int = 128,
x_dim: int = X_DIM,
dropout: float = 0.1,
conditioning: str = "embedding",
) -> None:
super().__init__()
self.cond_enc = ConditionEncoder(
pdg_vocab=pdg_vocab,
mat_vocab=mat_vocab,
emb_dim=emb_dim,
out_dim=cond_out_dim,
conditioning=conditioning,
)
self.input_proj = nn.Linear(x_dim, hidden_dim)
self.blocks = nn.ModuleList(
[
ResBlock(hidden_dim, cond_out_dim, dropout=dropout)
for _ in range(n_blocks)
]
)
self.out_norm = nn.LayerNorm(hidden_dim)
self.out_proj = nn.Linear(hidden_dim, 1)
def forward(
self,
x: torch.Tensor,
cond_cont: torch.Tensor,
cond_cat: torch.Tensor,
) -> torch.Tensor:
cond = self.cond_enc(cond_cont, cond_cat)
h = self.input_proj(x)
for block in self.blocks:
h = block(h, cond)
return self.out_proj(self.out_norm(h)).squeeze(-1)
class WGANSecondaryGenerator(nn.Module):
"""Stage-2 WGAN-GP generator: single forward pass over all K_MAX slots.
Mirrors `SecondaryDecoder` minus the time embedding, the same way
`WGANGenerator` mirrors `DenoisingMLP` — takes noise `z` instead of `x_t`,
conditions on `SecondaryConditionEncoder`'s output alone.
"""
def __init__(
self,
pdg_vocab: int,
mat_vocab: int,
hidden_dim: int = 256,
n_blocks: int = 6,
emb_dim: int = 16,
cond_out_dim: int = 128,
stage1_proj_dim: int = 64,
sec_dim: int = SEC_DIM,
noise_dim: int = 64,
dropout: float = 0.1,
conditioning: str = "embedding",
) -> None:
super().__init__()
self.noise_dim = noise_dim
self.cond_enc = SecondaryConditionEncoder(
pdg_vocab=pdg_vocab,
mat_vocab=mat_vocab,
emb_dim=emb_dim,
cond_out_dim=cond_out_dim,
stage1_proj_dim=stage1_proj_dim,
out_dim=cond_out_dim,
conditioning=conditioning,
)
self.input_proj = nn.Linear(noise_dim, hidden_dim)
self.blocks = nn.ModuleList(
[
ResBlock(hidden_dim, cond_out_dim, dropout=dropout)
for _ in range(n_blocks)
]
)
self.out_proj = nn.Linear(hidden_dim, sec_dim)
def forward(
self,
z: torch.Tensor,
cond_cont: torch.Tensor,
cond_cat: torch.Tensor,
stage1_out: torch.Tensor,
) -> torch.Tensor:
cond = self.cond_enc(cond_cont, cond_cat, stage1_out)
x = self.input_proj(z)
for block in self.blocks:
x = block(x, cond)
return self.out_proj(x)
class SecondaryCritic(nn.Module):
"""Stage-2 WGAN-GP critic: scalar realism score over the flattened 90D slots."""
def __init__(
self,
pdg_vocab: int,
mat_vocab: int,
hidden_dim: int = 256,
n_blocks: int = 6,
emb_dim: int = 16,
cond_out_dim: int = 128,
stage1_proj_dim: int = 64,
sec_dim: int = SEC_DIM,
dropout: float = 0.1,
conditioning: str = "embedding",
) -> None:
super().__init__()
self.cond_enc = SecondaryConditionEncoder(
pdg_vocab=pdg_vocab,
mat_vocab=mat_vocab,
emb_dim=emb_dim,
cond_out_dim=cond_out_dim,
stage1_proj_dim=stage1_proj_dim,
out_dim=cond_out_dim,
conditioning=conditioning,
)
self.input_proj = nn.Linear(sec_dim, hidden_dim)
self.blocks = nn.ModuleList(
[
ResBlock(hidden_dim, cond_out_dim, dropout=dropout)
for _ in range(n_blocks)
]
)
self.out_norm = nn.LayerNorm(hidden_dim)
self.out_proj = nn.Linear(hidden_dim, 1)
def forward(
self,
x: torch.Tensor,
cond_cont: torch.Tensor,
cond_cat: torch.Tensor,
stage1_out: torch.Tensor,
) -> torch.Tensor:
cond = self.cond_enc(cond_cont, cond_cat, stage1_out)
h = self.input_proj(x)
for block in self.blocks:
h = block(h, cond)
return self.out_proj(self.out_norm(h)).squeeze(-1)
class Router(nn.Module):
"""Contract for a pluggable mixture-of-experts routing axis."""
def __init__(self, n_experts: int) -> None:
super().__init__()
self.n_experts = n_experts
self.gumbel = False
self.gumbel_tau = 1.0
def gate(self, cond_cont: torch.Tensor, cond_cat: torch.Tensor) -> torch.Tensor:
raise NotImplementedError
def combine_weights(
self, cond_cont: torch.Tensor, cond_cat: torch.Tensor
) -> torch.Tensor:
probs = self.gate(cond_cont, cond_cat)
if not (self.gumbel and self.training):
return probs
log_probs = torch.log(probs.clamp_min(1e-8))
return F.gumbel_softmax(log_probs, tau=self.gumbel_tau, hard=True, dim=-1)
def top1(self, cond_cont: torch.Tensor, cond_cat: torch.Tensor) -> torch.Tensor:
return self.gate(cond_cont, cond_cat).argmax(dim=-1)
def balance_loss(
self, cond_cont: torch.Tensor, cond_cat: torch.Tensor
) -> torch.Tensor:
importance = self.gate(cond_cont, cond_cat).sum(dim=0) # (n_experts,)
return (importance.std() / (importance.mean() + 1e-8)) ** 2
def classify_loss(
self, cond_cont: torch.Tensor, cond_cat: torch.Tensor, labels: torch.Tensor
) -> torch.Tensor:
return torch.zeros((), device=cond_cont.device)
def entropy_loss(
self, cond_cont: torch.Tensor, cond_cat: torch.Tensor
) -> torch.Tensor:
norm_entropy, _ = self.gate_stats(cond_cont, cond_cat)
return norm_entropy
def gate_stats(
self, cond_cont: torch.Tensor, cond_cat: torch.Tensor
) -> tuple[torch.Tensor, torch.Tensor]:
gate = self.gate(cond_cont, cond_cat) # (B, n_experts)
row_entropy = -(gate * (gate + 1e-8).log()).sum(dim=-1) # (B,)
norm_entropy = row_entropy.mean() / math.log(self.n_experts)
importance = gate.sum(dim=0) # (n_experts,)
return norm_entropy, importance
ROUTER_REGISTRY: dict[str, type[Router]] = {}
def register_router(name: str):
def decorator(cls: type[Router]) -> type[Router]:
ROUTER_REGISTRY[name] = cls
return cls
return decorator
def build_router(name: str, n_experts: int, **kwargs) -> Router:
if name not in ROUTER_REGISTRY:
raise ValueError(
f"unknown router type {name!r}; available: {sorted(ROUTER_REGISTRY)}"
)
cls = ROUTER_REGISTRY[name]
accepted = set(inspect.signature(cls.__init__).parameters) - {"self", "n_experts"}
filtered = {k: v for k, v in kwargs.items() if k in accepted}
return cls(n_experts=n_experts, **filtered)
def _bounded_interp(raw: torch.Tensor, lo: float, hi: float) -> torch.Tensor:
return lo + (hi - lo) * torch.sigmoid(raw)
def _inverse_bounded_interp(value: float, lo: float, hi: float) -> float:
p = min(max((value - lo) / (hi - lo), 1e-6), 1 - 1e-6)
return math.log(p / (1 - p))
@register_router("energy")
class EnergyRouter(Router):
def __init__(
self,
n_experts: int = 4,
temperature: float = 0.5,
learn_centers: bool = True,
energy_idx: int = 3,
centers_init: Sequence[float] | None = None,
learn_width: bool = False,
learn_temperature: bool = False,
width_min_ratio: float = 0.1,
width_max_ratio: float = 10.0,
) -> None:
super().__init__(n_experts)
if learn_width and learn_temperature:
raise ValueError("learn_width and learn_temperature are mutually exclusive")
self.temperature = temperature
self.energy_idx = energy_idx
self.learn_width = learn_width
self.learn_temperature = learn_temperature
if learn_width or learn_temperature:
if not (width_min_ratio < 1.0 < width_max_ratio):
raise ValueError(
f"width_min_ratio ({width_min_ratio}) and width_max_ratio "
f"({width_max_ratio}) must bracket 1.0"
)
self._width_lo = width_min_ratio * temperature
self._width_hi = width_max_ratio * temperature
raw0 = _inverse_bounded_interp(temperature, self._width_lo, self._width_hi)
if learn_width:
self.raw_width = nn.Parameter(torch.full((n_experts,), raw0))
else:
self.raw_temperature = nn.Parameter(torch.tensor(raw0))
if centers_init is None:
centers = torch.linspace(-2.0, 2.0, n_experts)
else:
if len(centers_init) != n_experts:
raise ValueError(
f"centers_init has {len(centers_init)} values, "
f"expected n_experts={n_experts}"
)
centers = torch.tensor(list(centers_init), dtype=torch.float32)
if learn_centers:
self.centers = nn.Parameter(centers)
else:
self.register_buffer("centers", centers)
def effective_width(self) -> torch.Tensor | float:
if self.learn_width:
return _bounded_interp(self.raw_width, self._width_lo, self._width_hi)
if self.learn_temperature:
return _bounded_interp(self.raw_temperature, self._width_lo, self._width_hi)
return self.temperature
def gate(self, cond_cont: torch.Tensor, cond_cat: torch.Tensor) -> torch.Tensor:
e = cond_cont[:, self.energy_idx].unsqueeze(-1) # (B, 1)
d2 = (e - self.centers.unsqueeze(0)) ** 2 # (B, n_experts)
return torch.softmax(-d2 / self.effective_width(), dim=-1)
@register_router("pdg")
class PdgRouter(Router):
def __init__(
self,
n_experts: int,
pdg_vocab: int,
emb_dim: int = 8,
temperature: float = 0.5,
learn_centers: bool = True,
) -> None:
super().__init__(n_experts)
self.temperature = temperature
self.pdg_emb = nn.Embedding(pdg_vocab, emb_dim)
centers = torch.randn(n_experts, emb_dim) * 0.1
if learn_centers:
self.centers = nn.Parameter(centers)
else:
self.register_buffer("centers", centers)
def gate(self, cond_cont: torch.Tensor, cond_cat: torch.Tensor) -> torch.Tensor:
e = self.pdg_emb(cond_cat[:, 0]) # (B, emb_dim)
d2 = ((e.unsqueeze(1) - self.centers.unsqueeze(0)) ** 2).sum(
-1
) # (B, n_experts)
return torch.softmax(-d2 / self.temperature, dim=-1)
@register_router("process")
class ProcessRouter(Router):
def __init__(
self,
n_experts: int,
pdg_vocab: int,
mat_vocab: int,
emb_dim: int = 8,
hidden_dim: int = 64,
) -> None:
super().__init__(n_experts)
self.pdg_emb = nn.Embedding(pdg_vocab, emb_dim)
self.mat_emb = nn.Embedding(mat_vocab, emb_dim)
self.classifier = nn.Sequential(
nn.Linear(COND_DIM + 2 * emb_dim, hidden_dim),
nn.SiLU(),
nn.Linear(hidden_dim, n_experts),
)
def logits(self, cond_cont: torch.Tensor, cond_cat: torch.Tensor) -> torch.Tensor:
pdg_e = self.pdg_emb(cond_cat[:, 0])
mat_e = self.mat_emb(cond_cat[:, 1])
h = torch.cat([cond_cont, pdg_e, mat_e], dim=-1)
return self.classifier(h)
def gate(self, cond_cont: torch.Tensor, cond_cat: torch.Tensor) -> torch.Tensor:
return torch.softmax(self.logits(cond_cont, cond_cat), dim=-1)
def classify_loss(
self, cond_cont: torch.Tensor, cond_cat: torch.Tensor, labels: torch.Tensor
) -> torch.Tensor:
return F.cross_entropy(self.logits(cond_cont, cond_cat), labels)
class ComposedRouter(Router):
def __init__(self, routers: list[Router]) -> None:
if not routers:
raise ValueError("ComposedRouter needs at least one sub-router")
n_experts = 1
for r in routers:
n_experts *= r.n_experts
super().__init__(n_experts)
self.routers = nn.ModuleList(routers)
def gate(self, cond_cont: torch.Tensor, cond_cat: torch.Tensor) -> torch.Tensor:
joint = self.routers[0].gate(cond_cont, cond_cat) # (B, n_0)
for router in self.routers[1:]:
g = router.gate(cond_cont, cond_cat) # (B, n_i)
joint = (joint.unsqueeze(-1) * g.unsqueeze(1)).flatten(
1
) # (B, prod so far)
return joint
def classify_loss(
self, cond_cont: torch.Tensor, cond_cat: torch.Tensor, labels: torch.Tensor
) -> torch.Tensor:
total = torch.zeros((), device=cond_cont.device)
for router in self.routers:
total = total + router.classify_loss(cond_cont, cond_cat, labels)
return total
def build_composed_router(specs: list[dict], **shared_kwargs) -> ComposedRouter:
routers = [
build_router(
spec["type"],
spec["n_experts"],
**{
**shared_kwargs,
**{k: v for k, v in spec.items() if k not in ("type", "n_experts")},
},
)
for spec in specs
]
return ComposedRouter(routers)
class ExpertTrunk(nn.Module):
def __init__(
self,
in_dim: int,
hidden_dim: int,
n_blocks: int,
merged_cond_dim: int,
dropout: float = 0.1,
) -> None:
super().__init__()
self.input_proj = nn.Linear(in_dim, hidden_dim)
self.blocks = nn.ModuleList(
[
ResBlock(hidden_dim, merged_cond_dim, dropout=dropout)
for _ in range(n_blocks)
]
)
self.out_proj = nn.Linear(hidden_dim, in_dim)
def forward(self, x: torch.Tensor, cond: torch.Tensor) -> torch.Tensor:
x = self.input_proj(x)
for block in self.blocks:
x = block(x, cond)
return self.out_proj(x)
def _route_forward(
experts: nn.ModuleList,
router: Router,
x: torch.Tensor,
cond: torch.Tensor,
cond_cont: torch.Tensor,
cond_cat: torch.Tensor,
training: bool,
) -> torch.Tensor:
if training:
weights = router.combine_weights(cond_cont, cond_cat) # (B, n_experts)
out = torch.zeros_like(x)
for i, expert in enumerate(experts):
out = out + weights[:, i : i + 1] * expert(x, cond)
return out
idx = router.top1(cond_cont, cond_cat) # (B,)
out = torch.zeros_like(x)
for i, expert in enumerate(experts):
mask = idx == i
if mask.any():
out[mask] = expert(x[mask], cond[mask])
return out
class RoutedDenoisingMLP(nn.Module):
def __init__(
self,
pdg_vocab: int,
mat_vocab: int,
router: Router,
expert_hidden_dim: int = 128,
expert_n_blocks: int = 3,
emb_dim: int = EMB_DIM,
time_dim: int = 64,
cond_out_dim: int = 128,
x_dim: int = X_DIM,
dropout: float = 0.1,
k_max: int = K_MAX,
conditioning: str = "embedding",
) -> None:
super().__init__()
self.router = router
self.time_emb = SinusoidalEmbedding(time_dim)
self.cond_enc = ConditionEncoder(
pdg_vocab=pdg_vocab,
mat_vocab=mat_vocab,
emb_dim=emb_dim,
out_dim=cond_out_dim,
conditioning=conditioning,
)
merged_cond_dim = time_dim + cond_out_dim
self.experts = nn.ModuleList(
[
ExpertTrunk(
x_dim,
expert_hidden_dim,
expert_n_blocks,
merged_cond_dim,
dropout=dropout,
)
for _ in range(router.n_experts)
]
)
self.n_sec_head = nn.Sequential(
nn.Linear(cond_out_dim, cond_out_dim),
nn.SiLU(),
nn.Linear(cond_out_dim, k_max + 1),
)
def forward(
self,
x_t: torch.Tensor,
t: torch.Tensor,
cond_cont: torch.Tensor,
cond_cat: torch.Tensor,
) -> torch.Tensor:
t_emb = self.time_emb(t)
c_emb = self.cond_enc(cond_cont, cond_cat)
cond = torch.cat([t_emb, c_emb], dim=-1)
return _route_forward(
self.experts, self.router, x_t, cond, cond_cont, cond_cat, self.training
)
def predict_n_sec(
self,
cond_cont: torch.Tensor,
cond_cat: torch.Tensor,
) -> torch.Tensor:
c_emb = self.cond_enc(cond_cont, cond_cat)
return self.n_sec_head(c_emb)
class RoutedSecondaryDecoder(nn.Module):
def __init__(
self,
pdg_vocab: int,
mat_vocab: int,
router: Router,
expert_hidden_dim: int = 128,
expert_n_blocks: int = 3,
emb_dim: int = EMB_DIM,
time_dim: int = 64,
cond_out_dim: int = 128,
stage1_proj_dim: int = 64,
sec_dim: int = SEC_DIM,
dropout: float = 0.1,
conditioning: str = "embedding",
) -> None:
super().__init__()
self.router = router
self.time_emb = SinusoidalEmbedding(time_dim)
self.cond_enc = SecondaryConditionEncoder(
pdg_vocab=pdg_vocab,
mat_vocab=mat_vocab,
emb_dim=emb_dim,
cond_out_dim=cond_out_dim,
stage1_proj_dim=stage1_proj_dim,
out_dim=cond_out_dim,
conditioning=conditioning,
)
merged_cond_dim = time_dim + cond_out_dim
self.experts = nn.ModuleList(
[
ExpertTrunk(
sec_dim,
expert_hidden_dim,
expert_n_blocks,
merged_cond_dim,
dropout=dropout,
)
for _ in range(router.n_experts)
]
)
def forward(
self,
x_t: torch.Tensor,
t: torch.Tensor,
cond_cont: torch.Tensor,
cond_cat: torch.Tensor,
stage1_out: torch.Tensor,
) -> torch.Tensor:
t_emb = self.time_emb(t)
c_emb = self.cond_enc(cond_cont, cond_cat, stage1_out)
cond = torch.cat([t_emb, c_emb], dim=-1)
return _route_forward(
self.experts, self.router, x_t, cond, cond_cont, cond_cat, self.training
)
_STAGE1_MODEL_KEYS = {
"pdg_vocab",
"mat_vocab",
"hidden_dim",
"n_blocks",
"emb_dim",
"dropout",
"k_max",
"conditioning",
}
_SEC_DECODER_MODEL_KEYS = {
"pdg_vocab",
"mat_vocab",
"hidden_dim",
"n_blocks",
"emb_dim",
"dropout",
"conditioning",
}
_WGAN_GENERATOR_MODEL_KEYS = _STAGE1_MODEL_KEYS | {"noise_dim"}
_WGAN_SEC_GENERATOR_MODEL_KEYS = _SEC_DECODER_MODEL_KEYS | {"noise_dim"}
_CRITIC_MODEL_KEYS = _STAGE1_MODEL_KEYS - {"k_max"}
_AXIS_KEY_RE = re.compile(r"^axis(\d+)_(.+)$")
def _parse_composed_axes(router_cfg: dict) -> list[dict]:
axes: dict[int, dict] = {}
for key, value in router_cfg.items():
m = _AXIS_KEY_RE.match(key)
if m is None:
continue
idx, field = int(m.group(1)), m.group(2)
axes.setdefault(idx, {})[field] = value
missing = set(range(len(axes))) - axes.keys()
if missing:
raise ValueError(f"composed router config has gaps at axis indices {missing}")
return [axes[i] for i in range(len(axes))]
_VOCAB_SCOPED_ROUTER_TYPES = ("pdg", "process")
def _check_router_conditioning_compat(
router_types: list[str], conditioning: str
) -> None:
bad = sorted(set(router_types) & set(_VOCAB_SCOPED_ROUTER_TYPES))
if bad and conditioning == "physical":
raise ValueError(
f"router type(s) {bad} always use a training-vocab PDG embedding, "
"which is incompatible with conditioning='physical' (whose whole "
"point is generalizing beyond that vocab) — pick a different "
"router type (e.g. 'energy') or use conditioning='embedding'."
)
def _build_router_from_cfg(
router_cfg: dict, pdg_vocab: int, mat_vocab: int, conditioning: str = "embedding"
) -> Router:
shared_vocab = dict(pdg_vocab=pdg_vocab, mat_vocab=mat_vocab)
if router_cfg["type"] == "composed":
axes = _parse_composed_axes(router_cfg)
_check_router_conditioning_compat([a["type"] for a in axes], conditioning)
router = build_composed_router(axes, **shared_vocab)
router.gumbel = bool(router_cfg.get("gumbel", False))
return router
_check_router_conditioning_compat([router_cfg["type"]], conditioning)
router_kwargs = {
k: v for k, v in router_cfg.items() if k not in ("enabled", "type", "n_experts")
}
router_kwargs.setdefault("pdg_vocab", pdg_vocab)
router_kwargs.setdefault("mat_vocab", mat_vocab)
router = build_router(router_cfg["type"], router_cfg["n_experts"], **router_kwargs)
router.gumbel = bool(router_cfg.get("gumbel", False))
return router
def build_models(model_config: dict) -> tuple[nn.Module, nn.Module]:
if model_config.get("mode") == "wgan":
stage1 = WGANGenerator(
**{k: v for k, v in model_config.items() if k in _WGAN_GENERATOR_MODEL_KEYS}
)
sec_decoder = WGANSecondaryGenerator(
**{
k: v
for k, v in model_config.items()
if k in _WGAN_SEC_GENERATOR_MODEL_KEYS
}
)
return stage1, sec_decoder
router_cfg = model_config.get("router")
if router_cfg and router_cfg.get("enabled"):
pdg_vocab = model_config["pdg_vocab"]
mat_vocab = model_config["mat_vocab"]
shared = dict(
pdg_vocab=pdg_vocab,
mat_vocab=mat_vocab,
expert_hidden_dim=model_config.get("expert_hidden_dim")
or model_config.get("hidden_dim", 128),
expert_n_blocks=model_config.get("expert_n_blocks")
or model_config.get("n_blocks", 3),
emb_dim=model_config.get("emb_dim", EMB_DIM),
dropout=model_config.get("dropout", 0.1),
conditioning=model_config.get("conditioning", "embedding"),
)
conditioning = shared["conditioning"]
stage1 = RoutedDenoisingMLP(
router=_build_router_from_cfg(
router_cfg, pdg_vocab, mat_vocab, conditioning
),
k_max=model_config.get("k_max", K_MAX),
**shared,
)
sec_decoder = RoutedSecondaryDecoder(
router=_build_router_from_cfg(
router_cfg, pdg_vocab, mat_vocab, conditioning
),
**shared,
)
return stage1, sec_decoder
stage1 = DenoisingMLP(
**{k: v for k, v in model_config.items() if k in _STAGE1_MODEL_KEYS}
)
sec_decoder = SecondaryDecoder(
**{k: v for k, v in model_config.items() if k in _SEC_DECODER_MODEL_KEYS}
)
return stage1, sec_decoder
def build_critics(model_config: dict) -> tuple[nn.Module, nn.Module]:
critic = Critic(
**{k: v for k, v in model_config.items() if k in _CRITIC_MODEL_KEYS}
)
sec_critic = SecondaryCritic(
**{k: v for k, v in model_config.items() if k in _SEC_DECODER_MODEL_KEYS}
)
return critic, sec_critic