Files
hao-ai-lab-FastVideo/v2/platform/backends/cpu.py
T
Will Lin 1fe50c0092 [refactor] v2: group flat top-level into planes; isolate vendored under _vendor/
The v2 top level had grown to ~27 dirs + 13 loose files — half of them
single-concept abstraction shells (memory/ 86 LOC, transport/ 222, parity/ 178,
extend/ 226) and half vendored fastvideo code sitting as peers to the actual v2
design. Regroup to mirror README section 3 "Planes & dependency order":

  core/     enums+types, card, loop, program, parity, request, parallel
            (the model-native contracts; no kernels)
  runtime/  + folded-in substrate: cache, memory, transport, extend
            (the import graph shows only runtime consumes them; compile/cudagraph
            already lived here)
  serving/  + deploy/ (products / fleet)
  _vendor/  all copied fastvideo: models, layers, attention, configs, distributed,
            platforms, api, hooks, logging_utils, third_party + fastvideo_args/
            utils/logger/envs/forward_context — internal layout unchanged, still
            mirrors upstream for diffing

28 dirs + 13 root files -> 8 dirs + 6 root files. Pure mechanical move: 947
absolute-import paths rewritten (v2.X -> v2.{core,runtime,serving,_vendor}.X),
boundary-anchored so platform/ (native dispatch) and platforms/ (vendored CUDA
detect) no longer collide and neither does hooks/ vs extend/. Deleted the empty
v2/loader/. README section 3 + 16 updated; stale test count corrected
(34 files/216 tests -> 22 files/143 tests).

Validated: `import v2` stays torch-free; `v2/run_tests.py` and `pytest v2/tests/`
-> 143 passed, 2 skipped on the numpy toy backend. (On a GPU box force the toy
backend with CUDA_VISIBLE_DEVICES="" or detect() picks cuda.) No external importer
changed — examples use the re-exported `from v2 import VideoGenerator`.
2026-07-04 17:15:34 +00:00

29 lines
1.4 KiB
Python

"""CPU / numpy backend — the terminal rung and parity oracle.
This backend registers the numpy reference kernels. It is the bottom of every device fallback
chain: any op a richer backend hasn't implemented resolves here, and every other backend's output
is checked against this one (the consistency ladder's C0/C1 oracle).
Components are NOT registered here: the card's ``ComponentSpec.factory`` *is* the cpu/numpy
component rung (``Platform.build_component`` falls back to it when no ``(kind, device, …)`` cell
matches). That keeps every existing card working with zero registration.
"""
from __future__ import annotations
from v2.core.loop.sampler import flow_match_euler_step, flow_sde_step_with_logprob
from v2.platform.registry import FLOW_MATCH_STEP, FLOW_SDE_STEP, register_kernel
# The numpy solver primitives, registered as the terminal (cpu, numpy) kernels. These are the exact
# same functions the loops used to call directly — so dispatching through the registry on a CPU box
# is bit-for-bit identical to the pre-registry behavior.
register_kernel(FLOW_MATCH_STEP,
flow_match_euler_step,
device="cpu",
arch="numpy",
source="loop.sampler:flow_match_euler_step")
register_kernel(FLOW_SDE_STEP,
flow_sde_step_with_logprob,
device="cpu",
arch="numpy",
source="loop.sampler:flow_sde_step_with_logprob")