---

name: modeling-and-inference description: "Operate FastReID model registries, safe CPU construction, feature extraction, checkpoint loading, and rank utility imports." disable-model-invocation: true metadata: disco-role: operating license: Apache 2.0

FastReID modeling and inference

Use this sub-skill when the task is about FastReID model construction, backbone/head/meta-architecture registries, CPU-safe forward checks, predictor-style feature extraction, checkpoint expectations, or rank/rerank utility imports.

Route elsewhere when the request is primarily about:

• full training/eval CLI, resume, distributed launch, logs, or benchmark metrics: use ../training-and-evaluation/.
• dataset registration, person-ID layouts, dataloaders, samplers, or transforms: use ../data-and-datasets/.
• ONNX/Caffe/TensorRT export, runtime deployment, visualization CLIs, or project extensions: use ../deployment-and-projects/.
• environment setup, source-only package import, config inheritance, or model-zoo recipe selection: use ../setup-and-configuration/.

Operating references and scripts

• references/model-api.md: use for builder imports, registry names, model family mapping, config keys, tensor contracts, and layer/head/loss vocabulary.
• references/inference-workflows.md: use for CPU dry-runs, DefaultPredictor-style checkpoint loading, demo-style BGR image preprocessing, feature normalization, and rank/rerank utility usage.
• references/troubleshooting.md: use to debug missing weights, unwanted ImageNet pretrain downloads, device mismatches, shape errors, rank import mismatches, Cython fallback warnings, and missing OpenCV.
• scripts/model_forward_smoke.py: run a no-download CPU model construction and random-tensor forward check; accepts an optional config path and explicit repository source path.
• scripts/feature_extraction_smoke.py: run a no-download feature-extraction preprocessing/model smoke; accepts an optional local image, optional local checkpoint, optional config path, and explicit repository source path.

Safe defaults

• FastReID defaults MODEL.DEVICE to cuda; the bundled smoke scripts override it to cpu.
• Recipe configs often enable MODEL.BACKBONE.PRETRAIN; the bundled smoke scripts override it to False so they do not download backbone weights.
• Configs may set MODEL.WEIGHTS; the feature smoke ignores config weights unless --weights is explicitly supplied as a local file.
• Inference tensors are float32 in (B, C, H, W) layout and model outputs are feature tensors in eval mode for standard ReID heads.
• Demo-style image inference starts from OpenCV-style BGR arrays, converts BGR to RGB, resizes to INPUT.SIZE_TEST, transposes to CHW, adds a batch dimension, and returns L2-normalized features when requested by the caller.