chumpy/ch.py

from __future__ import annotations
"""
PRIMA: Boosting Animal Mesh Recovery with Biological Priors and Test-Time Adaptation

Official implementation of the paper:
"PRIMA: Boosting Animal Mesh Recovery with Biological Priors and Test-Time Adaptation"
by Xiaohang Yu, Ti Wang, and Mackenzie Weygandt Mathis
Licensed under a modified MIT license
"""


"""``chumpy.ch`` namespace expected by legacy SMAL pickles."""

import numpy as np


class Ch:
    """Minimal stand-in for ``chumpy.ch.Ch`` (unpickling only)."""

    def __init__(self, *args, **kwargs):
        self._data = None
        if args:
            self._data = np.asarray(args[0])

    def _resolve(self) -> np.ndarray:
        # Real chumpy Ch instances store the underlying ndarray on attribute ``x``;
        # legacy pickles unpickle by restoring ``__dict__`` without calling ``__init__``,
        # so try common attribute names before falling back to ``_data``.
        r = self.__dict__.get("r")
        if isinstance(r, np.ndarray):
            return np.asarray(r)
        for attr in ("x", "_x", "_data"):
            val = self.__dict__.get(attr)
            if val is not None:
                return np.asarray(val)
        data = self.__dict__.get("_data")
        if data is not None:
            return np.asarray(data)
        return np.zeros((), dtype=np.float32)

    def r(self) -> np.ndarray:
        """Match real chumpy API (``ch.r()`` returns the underlying array)."""
        return self._resolve()

    def __array__(self, dtype=None):
        arr = self._resolve()
        if dtype is not None:
            arr = arr.astype(dtype, copy=False)
        return arr


class ChArray(np.ndarray):
    """Minimal stand-in for ``chumpy.ch.ChArray``."""


def _unwrap_ch(value, dtype=np.float32) -> np.ndarray:
    """Resolve a chumpy ``Ch`` (method, property, or unpickled ``r``/``x`` attrs) to ndarray."""
    if isinstance(value, Ch):
        return np.asarray(value._resolve(), dtype=dtype)
    r = getattr(value, "r", None)
    if isinstance(r, np.ndarray):
        return np.asarray(r, dtype=dtype)
    if callable(r):
        return np.asarray(r(), dtype=dtype)
    for attr in ("x", "_x", "_data"):
        val = getattr(value, attr, None)
        if val is not None:
            return np.asarray(val, dtype=dtype)
    raise TypeError(f"Cannot materialize chumpy-like object: {type(value)!r}")


def materialize(value, dtype=np.float32) -> np.ndarray:
    """Recursively unwrap ``Ch`` / object arrays from legacy SMAL pickles."""
    if isinstance(value, Ch) or (
        type(value).__name__ == "Ch"
        and hasattr(value, "r")
        and not isinstance(value, (np.ndarray, list, tuple, dict, str, bytes))
    ):
        return _unwrap_ch(value, dtype=dtype)
    if isinstance(value, np.ndarray):
        if value.dtype == object:
            flat = [materialize(x, dtype=dtype) for x in value.ravel()]
            return np.stack(flat).reshape(value.shape)
        return np.asarray(value, dtype=dtype)
    if isinstance(value, (list, tuple)):
        return np.asarray([materialize(x, dtype=dtype) for x in value], dtype=dtype)
    return np.asarray(value, dtype=dtype)


__all__ = ["Ch", "ChArray", "materialize"]