'''
This module requires extra installs: ``pip install opendp[numpy]``
For convenience, all the functions of this module are also available from :py:mod:`opendp.prelude`.
We suggest importing under the conventional name ``dp``:
.. code:: python
>>> import opendp.prelude as dp
The methods of this module will then be accessible at ``dp.numpy``.
'''
from __future__ import annotations
from typing import NamedTuple, Literal
from opendp.mod import Domain, Metric, Transformation
from opendp.typing import RuntimeTypeDescriptor, ELEMENTARY_TYPES
from opendp._convert import ATOM_MAP
from opendp._lib import import_optional_dependency
from opendp.extras._utilities import register_transformation
import typing
if typing.TYPE_CHECKING: # pragma: no cover
import numpy # type: ignore[import-not-found]
def _check_norm_and_p(norm: float | None, p: int | None):
"""Checks that a scalar L`p` `norm` is well-defined"""
if (norm is None) != (p is None):
raise ValueError("norm and p must both be set")
if norm is not None:
if isinstance(norm, int):
norm = float(norm)
if not isinstance(norm, float):
raise ValueError("norm must be float")
if norm < 0.0:
raise ValueError("norm must be non-negative")
if p not in {None, 1, 2}:
raise ValueError("p must be 1 or 2")
def _check_nonnegative_int(v: int | None, name: str):
if v is not None:
if not isinstance(v, int):
raise ValueError(f"{name} must be an integer")
if v < 0:
raise ValueError(f"{name} must be non-negative")
def _fmt_attrs(attrs: NamedTuple) -> str:
return ", ".join(f"{k}={v}" for k, v in attrs._asdict().items() if v is not None)
[docs]
def array2_domain(
*,
norm: float | None = None,
p: Literal[1, 2, None] = None,
origin=None,
size: int | None = None,
num_columns: int | None = None,
T: RuntimeTypeDescriptor | None = None,
) -> Domain:
"""Construct a Domain representing 2-dimensional numpy arrays.
:param norm: each row in x is bounded by the norm
:param p: designates L`p` norm
:param origin: center of the norm region. Assumed to be at zero
:param size: number of rows in data
:param num_columns: number of columns in the data
:param T: atom type
"""
np = import_optional_dependency('numpy')
import opendp.prelude as dp
_check_norm_and_p(norm, p)
if norm is not None:
# normalize origin to a scalar
origin = origin if origin is not None else 0.0
if norm is None and origin is not None:
raise ValueError("origin may only be set if data has bounded norm")
if isinstance(origin, (int, float)):
# normalize origin to a 1d-ndarray
origin = np.array(origin)
if isinstance(origin, np.ndarray):
if origin.dtype.kind in {"i", "u"}:
origin = origin.astype(float)
if origin.dtype.kind != "f":
raise ValueError("origin array must be numeric")
if origin.ndim == 0:
if origin != 0:
raise ValueError("scalar origin must be zero")
if num_columns is not None:
# normalize to a 1d-ndarray
origin = np.repeat(origin, num_columns)
if origin.ndim == 1:
if num_columns is None:
num_columns = origin.size
if num_columns != origin.size:
raise ValueError(f"origin must have num_columns={num_columns} values")
if origin.ndim not in {0, 1}:
raise ValueError("origin must have 0 or 1 dimensions")
elif origin is not None:
raise ValueError("origin must be a scalar or ndarray")
_check_nonnegative_int(size, "size")
_check_nonnegative_int(num_columns, "num_columns")
T = T or ELEMENTARY_TYPES.get(origin.dtype.type)
if T is None:
raise ValueError("must specify T, the type of data in the array")
T = dp.RuntimeType.parse(T)
if T not in ATOM_MAP:
raise ValueError("T must be in an elementary type")
def member(x):
if not isinstance(x, np.ndarray):
raise TypeError("must be a numpy ndarray")
T_actual = ELEMENTARY_TYPES.get(x.dtype.type)
if T_actual != T:
raise TypeError(f"expected data of type {T}, got {T_actual}")
if x.ndim != 2:
raise ValueError("Expected 2-dimensional array")
if num_columns is not None and x.shape[1] != num_columns:
raise ValueError(f"must have {num_columns} columns")
if origin is not None:
x = x - origin
if norm is not None:
max_norm = np.linalg.norm(x, ord=p, axis=1).max()
if max_norm > norm:
raise ValueError(f"row norm is too large. {max_norm} > {norm}")
if size is not None and len(x) != size:
raise ValueError(f"expected exactly {size} rows")
return True
class NPArray2Descriptor(NamedTuple):
origin: numpy.ndarray | None
norm: float | None
p: Literal[1, 2, None]
size: int | None
num_columns: int | None
T: str | dp.RuntimeType
desc = NPArray2Descriptor(
origin=origin,
norm=norm,
p=p,
size=size,
num_columns=num_columns,
T=T,
)
return dp.user_domain(f"NPArray2Domain({_fmt_attrs(desc)})", member, desc)
def _sscp_domain(
*,
norm: float | None = None,
p: Literal[1, 2, None] = None,
size: int | None = None,
num_features: int | None = None,
T: RuntimeTypeDescriptor = float,
) -> Domain:
"""The domain of sums of squares and cross products matrices formed by computing x^Tx,
for some dataset x.
:param norm: each row in x is bounded by the norm
:param p: designates L`p` norm
:param size: number of rows in data
:param num_features: number of rows/columns in the matrix
"""
import opendp.prelude as dp
np = import_optional_dependency('numpy')
_check_norm_and_p(norm, p)
_check_nonnegative_int(size, "size")
_check_nonnegative_int(num_features, "num_features")
if T is None:
raise ValueError("must specify T, the type of data in the array")
T = dp.RuntimeType.parse(T)
if T not in {dp.f32, dp.f64}:
raise ValueError("T must be a float type")
def member(x):
if not isinstance(x, np.ndarray):
raise TypeError("must be a numpy ndarray")
T_actual = ELEMENTARY_TYPES.get(x.dtype.type)
if T_actual != T:
raise TypeError(f"expected data of type {T}, got {T_actual}")
if x.shape != (num_features,) * 2:
raise ValueError(f"expected a square array with {num_features} features")
return True
class NPSSCPDescriptor(NamedTuple):
num_features: int | None
norm: float | None
p: Literal[1, 2, None]
size: int | None
T: str | dp.RuntimeType
desc = NPSSCPDescriptor(
num_features=num_features,
norm=norm,
p=p,
size=size,
T=T,
)
return dp.user_domain(f"NPSSCPDomain({_fmt_attrs(desc)})", member, desc)
[docs]
def make_np_clamp(
input_domain: Domain, input_metric: Metric, norm, p, origin=None
) -> Transformation:
"""Construct a Transformation that clamps the norm of input data.
:param input_domain: instance of `array2_domain(...)`
:param input_metric: instance of `symmetric_distance()`
:param norm: clamp each row to this norm. Required if data is not already bounded
:param p: designates L`p` norm
:param origin: norm clamping is centered on this point. Defaults to zero
"""
import opendp.prelude as dp
np = import_optional_dependency('numpy')
dp.assert_features("contrib")
norm = float(norm)
if norm < 0.0:
raise ValueError("norm must not be negative")
if p not in {1, 2}:
raise ValueError("order p must be 1 or 2")
if origin is None:
origin = 0.0
def function(arg):
arg = arg.copy()
arg -= origin
# may have to run multiple times due to FP rounding
current_norm = np.linalg.norm(arg, ord=p, axis=1, keepdims=True)
while current_norm.max() > norm:
arg /= np.maximum(current_norm / norm, 1)
current_norm = np.linalg.norm(arg, ord=p, axis=1, keepdims=True)
arg += origin
return arg
kwargs = input_domain.descriptor._asdict() | {
"norm": norm,
"p": p,
"origin": origin,
}
return dp.t.make_user_transformation(
input_domain,
input_metric,
dp.numpy.array2_domain(**kwargs),
input_metric,
function,
lambda d_in: d_in,
)
# generate then variant of the constructor
# TODO: Show this in the API Reference?
then_np_clamp = register_transformation(make_np_clamp)
