def _get_context(ctx_id, ctx=None):
    if ctx is None:
        ctx = _get_current_context()

    parent = ctx._parent if ctx._parent is not None else ctx
    if parent._id_obj == ctx_id:
        return parent

    return parent._all_child_contexts[ctx_id]
Reduce the rank of the matrix by dropping all vectors.
dataset/ETHPy150Open manahl/mdf/mdf/context.py/_get_context--crossover with--dataset/ETHPy150Open scipy/scipy/scipy/optimize/nonlin.py/LowRankMatrix.restart_reduce