recap-t2i-evaluation-code-2026 / eval_code /scripts /compute_longclip_retrieval_margin.py
Authors
Initial anonymous NeurIPS 2026 E&D code and results release
7f59fb7 verified
#!/usr/bin/env python3
"""Compute LongCLIP-style image-caption retrieval separability.
This metric is a frozen dual-encoder compatibility diagnostic, not a
faithfulness certificate. It reports whether each caption distinguishes its
paired image from same-slice negatives, while also reporting text truncation.
"""
from __future__ import annotations
import argparse
import hashlib
import json
import random
import time
from pathlib import Path
from typing import Any
import numpy as np
import torch
from PIL import Image, ImageFile
ImageFile.LOAD_TRUNCATED_IMAGES = True
def parse_args() -> argparse.Namespace:
parser = argparse.ArgumentParser(description=__doc__)
parser.add_argument("--surface", action="append", required=True, metavar="LABEL=JSONL")
parser.add_argument("--output-dir", required=True)
parser.add_argument("--model", default="zer0int/LongCLIP-GmP-ViT-L-14")
parser.add_argument("--max-records", type=int, default=None)
parser.add_argument("--sample-records", type=int, default=None)
parser.add_argument("--sample-seed", type=int, default=0)
parser.add_argument("--batch-size", type=int, default=64)
parser.add_argument("--retrieval-block-size", type=int, default=512)
parser.add_argument("--max-length", type=int, default=248)
parser.add_argument("--device", default="cuda")
parser.add_argument("--dtype", default="float16", choices=["float16", "bfloat16", "float32"])
parser.add_argument("--bootstrap-reps", type=int, default=1000)
parser.add_argument("--trust-remote-code", action="store_true")
parser.add_argument("--save-embeddings", action="store_true")
return parser.parse_args()
def torch_dtype(name: str) -> torch.dtype:
return {"float16": torch.float16, "bfloat16": torch.bfloat16, "float32": torch.float32}[name]
def parse_surface(spec: str) -> tuple[str, Path]:
if "=" not in spec:
raise ValueError(f"--surface must be LABEL=JSONL: {spec}")
label, path = spec.split("=", 1)
return label, Path(path)
def stable_float(*parts: object) -> float:
raw = ":".join(str(part) for part in parts)
digest = hashlib.blake2b(raw.encode("utf-8"), digest_size=8).digest()
return int.from_bytes(digest, "big") / 2**64
def image_path(row: dict[str, Any]) -> str | None:
image = row.get("image") if isinstance(row.get("image"), dict) else {}
local = image.get("local_abs_path") or row.get("image_abs_path") or row.get("image_path")
if isinstance(local, str) and local:
return local
return None
def load_surface(path: Path) -> list[dict[str, Any]]:
rows: list[dict[str, Any]] = []
with path.open("r", encoding="utf-8") as handle:
for line in handle:
if not line.strip():
continue
row = json.loads(line)
caption = row.get("caption")
if isinstance(caption, str) and caption.strip():
rows.append(row)
return rows
def align_rows(surface_rows: dict[str, list[dict[str, Any]]], sample_records: int | None, max_records: int | None, seed: int) -> dict[str, list[dict[str, Any]]]:
labels = list(surface_rows)
n = min(len(surface_rows[label]) for label in labels)
indices = list(range(n))
if sample_records is not None:
indices.sort(key=lambda i: stable_float(seed, i))
indices = indices[:sample_records]
indices.sort()
elif max_records is not None:
indices = indices[:max_records]
return {label: [surface_rows[label][i] for i in indices] for label in labels}
def load_model(model_id: str, device: str, dtype_name: str, trust_remote_code: bool):
from transformers import AutoImageProcessor, AutoModel, AutoTokenizer
dtype = torch_dtype(dtype_name)
tokenizer = AutoTokenizer.from_pretrained(model_id, trust_remote_code=trust_remote_code)
image_processor = AutoImageProcessor.from_pretrained(model_id, trust_remote_code=trust_remote_code)
model = AutoModel.from_pretrained(model_id, trust_remote_code=trust_remote_code, torch_dtype=dtype)
model.eval().to(device)
return tokenizer, image_processor, model
def normalize(x: torch.Tensor) -> torch.Tensor:
return torch.nn.functional.normalize(x.float(), dim=-1)
def pooled_tensor(output: Any) -> torch.Tensor:
"""Return a tensor embedding from HF tensor/model-output variants."""
if isinstance(output, torch.Tensor):
return output
pooler_output = getattr(output, "pooler_output", None)
if isinstance(pooler_output, torch.Tensor):
return pooler_output
image_embeds = getattr(output, "image_embeds", None)
if isinstance(image_embeds, torch.Tensor):
return image_embeds
text_embeds = getattr(output, "text_embeds", None)
if isinstance(text_embeds, torch.Tensor):
return text_embeds
last_hidden_state = getattr(output, "last_hidden_state", None)
if isinstance(last_hidden_state, torch.Tensor):
return last_hidden_state[:, 0]
if isinstance(output, (tuple, list)) and output and isinstance(output[0], torch.Tensor):
first = output[0]
return first[:, 0] if first.ndim == 3 else first
raise TypeError(f"Cannot extract pooled tensor from {type(output)!r}")
def encode_texts(tokenizer: Any, model: Any, texts: list[str], device: str, max_length: int, batch_size: int) -> tuple[np.ndarray, np.ndarray]:
embs: list[np.ndarray] = []
lengths: list[int] = []
with torch.inference_mode():
for start in range(0, len(texts), batch_size):
batch = texts[start : start + batch_size]
raw = tokenizer(batch, padding=False, truncation=False, add_special_tokens=True)
lengths.extend(len(ids) for ids in raw["input_ids"])
encoded = tokenizer(batch, padding=True, truncation=True, max_length=max_length, return_tensors="pt")
encoded = {k: v.to(device) for k, v in encoded.items()}
if hasattr(model, "get_text_features"):
features = pooled_tensor(model.get_text_features(**encoded))
else:
features = pooled_tensor(model(**encoded))
embs.append(normalize(features).cpu().numpy().astype("float32"))
return np.concatenate(embs, axis=0), np.asarray(lengths, dtype=np.int32)
def encode_images(image_processor: Any, model: Any, rows: list[dict[str, Any]], device: str, batch_size: int) -> tuple[np.ndarray, dict[str, Any]]:
embs: list[np.ndarray] = []
kept_indices: list[int] = []
failures: list[dict[str, Any]] = []
batch_images: list[Image.Image] = []
batch_indices: list[int] = []
def flush() -> None:
if not batch_images:
return
inputs = image_processor(images=batch_images, return_tensors="pt")
inputs = {k: v.to(device) for k, v in inputs.items()}
with torch.inference_mode():
if hasattr(model, "get_image_features"):
features = pooled_tensor(model.get_image_features(**inputs))
else:
features = pooled_tensor(model(**inputs))
embs.append(normalize(features).cpu().numpy().astype("float32"))
kept_indices.extend(batch_indices)
batch_images.clear()
batch_indices.clear()
for index, row in enumerate(rows):
path = image_path(row)
if path is None:
failures.append({"index": index, "reason": "missing_image_path"})
continue
try:
image = Image.open(path).convert("RGB")
except Exception as exc: # noqa: BLE001
failures.append({"index": index, "path": path, "reason": repr(exc)[:500]})
continue
batch_images.append(image)
batch_indices.append(index)
if len(batch_images) >= batch_size:
flush()
flush()
if embs:
arr = np.concatenate(embs, axis=0)
else:
arr = np.zeros((0, 0), dtype=np.float32)
return arr, {"kept_indices": kept_indices, "failures": failures}
def mean_ci(values: np.ndarray, reps: int, rng: np.random.Generator) -> dict[str, float]:
values = np.asarray(values, dtype=np.float64)
if values.size == 0:
return {"mean": float("nan"), "ci95_low": float("nan"), "ci95_high": float("nan")}
if reps <= 0 or values.size == 1:
mean = float(values.mean())
return {"mean": mean, "ci95_low": mean, "ci95_high": mean}
means = np.empty(reps, dtype=np.float64)
n = values.size
for i in range(reps):
means[i] = values[rng.integers(0, n, n)].mean()
return {
"mean": float(values.mean()),
"ci95_low": float(np.percentile(means, 2.5)),
"ci95_high": float(np.percentile(means, 97.5)),
}
def retrieval_metrics(image_emb: np.ndarray, text_emb: np.ndarray, block_size: int) -> dict[str, np.ndarray]:
n = min(len(image_emb), len(text_emb))
pos = np.sum(image_emb[:n] * text_emb[:n], axis=1).astype(np.float32)
max_i2t = np.full(n, -np.inf, dtype=np.float32)
max_t2i = np.full(n, -np.inf, dtype=np.float32)
rank_i2t = np.ones(n, dtype=np.int32)
rank_t2i = np.ones(n, dtype=np.int32)
for image_start in range(0, n, block_size):
image_end = min(image_start + block_size, n)
image_block = image_emb[image_start:image_end]
image_idx = np.arange(image_start, image_end)
for text_start in range(0, n, block_size):
text_end = min(text_start + block_size, n)
text_block = text_emb[text_start:text_end]
text_idx = np.arange(text_start, text_end)
sims = image_block @ text_block.T
diag_mask = image_idx[:, None] == text_idx[None, :]
masked = sims.copy()
masked[diag_mask] = -np.inf
max_i2t[image_start:image_end] = np.maximum(max_i2t[image_start:image_end], masked.max(axis=1))
max_t2i[text_start:text_end] = np.maximum(max_t2i[text_start:text_end], masked.max(axis=0))
greater_i2t = sims > pos[image_start:image_end, None]
greater_i2t[diag_mask] = False
rank_i2t[image_start:image_end] += greater_i2t.sum(axis=1).astype(np.int32)
greater_t2i = sims > pos[text_start:text_end][None, :]
greater_t2i[diag_mask] = False
rank_t2i[text_start:text_end] += greater_t2i.sum(axis=0).astype(np.int32)
return {
"pos": pos,
"i2t_margin": (pos - max_i2t).astype(np.float32),
"t2i_margin": (pos - max_t2i).astype(np.float32),
"i2t_r1": (rank_i2t <= 1).astype(np.float32),
"i2t_r5": (rank_i2t <= 5).astype(np.float32),
"t2i_r1": (rank_t2i <= 1).astype(np.float32),
"t2i_r5": (rank_t2i <= 5).astype(np.float32),
}
def main() -> int:
args = parse_args()
started = time.time()
output_dir = Path(args.output_dir)
output_dir.mkdir(parents=True, exist_ok=True)
surface_specs = dict(parse_surface(spec) for spec in args.surface)
raw_rows = {label: load_surface(path) for label, path in surface_specs.items()}
rows = align_rows(raw_rows, args.sample_records, args.max_records, args.sample_seed)
labels = list(rows)
if not labels:
raise SystemExit("No surfaces provided")
tokenizer, image_processor, model = load_model(args.model, args.device, args.dtype, args.trust_remote_code)
image_emb, image_info = encode_images(image_processor, model, rows[labels[0]], args.device, args.batch_size)
kept_indices = image_info["kept_indices"]
rng = np.random.default_rng(args.sample_seed)
summaries: dict[str, Any] = {}
text_cache: dict[str, np.ndarray] = {}
token_cache: dict[str, np.ndarray] = {}
for label in labels:
kept_rows = [rows[label][index] for index in kept_indices]
texts = [str(row["caption"]) for row in kept_rows]
text_emb, token_lengths = encode_texts(tokenizer, model, texts, args.device, args.max_length, args.batch_size)
text_cache[label] = text_emb
token_cache[label] = token_lengths
metrics = retrieval_metrics(image_emb, text_emb, args.retrieval_block_size)
summaries[label] = {
"rows": int(len(texts)),
"token_mean": float(token_lengths.mean()) if len(token_lengths) else 0.0,
"token_p50": float(np.percentile(token_lengths, 50)) if len(token_lengths) else 0.0,
"token_p95": float(np.percentile(token_lengths, 95)) if len(token_lengths) else 0.0,
"truncated_rate_gt_limit": float((token_lengths > args.max_length).mean()) if len(token_lengths) else 0.0,
"pos_score": mean_ci(metrics["pos"], args.bootstrap_reps, rng),
"i2t_margin": mean_ci(metrics["i2t_margin"], args.bootstrap_reps, rng),
"t2i_margin": mean_ci(metrics["t2i_margin"], args.bootstrap_reps, rng),
"i2t_r_at_1": mean_ci(metrics["i2t_r1"], args.bootstrap_reps, rng),
"i2t_r_at_5": mean_ci(metrics["i2t_r5"], args.bootstrap_reps, rng),
"t2i_r_at_1": mean_ci(metrics["t2i_r1"], args.bootstrap_reps, rng),
"t2i_r_at_5": mean_ci(metrics["t2i_r5"], args.bootstrap_reps, rng),
}
payload = {
"model": args.model,
"max_length": args.max_length,
"surface_inputs": {label: str(path) for label, path in surface_specs.items()},
"labels": labels,
"image_rows": len(rows[labels[0]]),
"image_kept": len(kept_indices),
"image_failures": image_info["failures"][:100],
"retrieval_block_size": args.retrieval_block_size,
"bootstrap_reps": args.bootstrap_reps,
"seconds": round(time.time() - started, 2),
"summaries": summaries,
}
summary_path = output_dir / "longclip_retrieval_summary.json"
summary_path.write_text(json.dumps(payload, indent=2, ensure_ascii=False), encoding="utf-8")
rows_tsv = [
[
"surface",
"rows",
"trunc_gt_248",
"tok_mean",
"tok_p95",
"pos_mean",
"pos_ci95",
"i2t_margin_mean",
"i2t_margin_ci95",
"i2t_r1",
"i2t_r5",
"t2i_margin_mean",
"t2i_margin_ci95",
"t2i_r1",
"t2i_r5",
]
]
for label in labels:
s = summaries[label]
rows_tsv.append(
[
label,
str(s["rows"]),
f"{s['truncated_rate_gt_limit']:.4f}",
f"{s['token_mean']:.2f}",
f"{s['token_p95']:.1f}",
f"{s['pos_score']['mean']:.6f}",
f"[{s['pos_score']['ci95_low']:.6f},{s['pos_score']['ci95_high']:.6f}]",
f"{s['i2t_margin']['mean']:.6f}",
f"[{s['i2t_margin']['ci95_low']:.6f},{s['i2t_margin']['ci95_high']:.6f}]",
f"{s['i2t_r_at_1']['mean']:.4f}",
f"{s['i2t_r_at_5']['mean']:.4f}",
f"{s['t2i_margin']['mean']:.6f}",
f"[{s['t2i_margin']['ci95_low']:.6f},{s['t2i_margin']['ci95_high']:.6f}]",
f"{s['t2i_r_at_1']['mean']:.4f}",
f"{s['t2i_r_at_5']['mean']:.4f}",
]
)
(output_dir / "longclip_retrieval_summary.tsv").write_text(
"\n".join("\t".join(row) for row in rows_tsv) + "\n",
encoding="utf-8",
)
if args.save_embeddings:
np.save(output_dir / "image_embeddings.npy", image_emb.astype(np.float16))
for label, emb in text_cache.items():
np.save(output_dir / f"text_embeddings_{label}.npy", emb.astype(np.float16))
np.save(output_dir / f"token_lengths_{label}.npy", token_cache[label])
print(json.dumps({"summary": str(summary_path), "rows": len(kept_indices), "labels": labels}, indent=2))
return 0
if __name__ == "__main__":
raise SystemExit(main())