Inzynierka/Lib/site-packages/sklearn/metrics/tests/test_dist_metrics.py
2023-06-02 12:51:02 +02:00

457 lines
16 KiB
Python

import itertools
import pickle
import copy
import numpy as np
import pytest
import scipy.sparse as sp
from scipy.spatial.distance import cdist
from sklearn.metrics import DistanceMetric
from sklearn.metrics._dist_metrics import (
BOOL_METRICS,
# Unexposed private DistanceMetric for 32 bit
DistanceMetric32,
)
from sklearn.utils import check_random_state
from sklearn.utils._testing import assert_allclose, create_memmap_backed_data
from sklearn.utils.fixes import sp_version, parse_version
def dist_func(x1, x2, p):
return np.sum((x1 - x2) ** p) ** (1.0 / p)
rng = check_random_state(0)
d = 4
n1 = 20
n2 = 25
X64 = rng.random_sample((n1, d))
Y64 = rng.random_sample((n2, d))
X32 = X64.astype("float32")
Y32 = Y64.astype("float32")
[X_mmap, Y_mmap] = create_memmap_backed_data([X64, Y64])
# make boolean arrays: ones and zeros
X_bool = (X64 < 0.3).astype(np.float64) # quite sparse
Y_bool = (Y64 < 0.7).astype(np.float64) # not too sparse
[X_bool_mmap, Y_bool_mmap] = create_memmap_backed_data([X_bool, Y_bool])
V = rng.random_sample((d, d))
VI = np.dot(V, V.T)
METRICS_DEFAULT_PARAMS = [
("euclidean", {}),
("cityblock", {}),
("minkowski", dict(p=(1, 1.5, 2, 3))),
("chebyshev", {}),
("seuclidean", dict(V=(rng.random_sample(d),))),
("mahalanobis", dict(VI=(VI,))),
("hamming", {}),
("canberra", {}),
("braycurtis", {}),
]
if sp_version >= parse_version("1.8.0.dev0"):
# Starting from scipy 1.8.0.dev0, minkowski now accepts w, the weighting
# parameter directly and using it is preferred over using wminkowski.
METRICS_DEFAULT_PARAMS.append(
("minkowski", dict(p=(1, 1.5, 3), w=(rng.random_sample(d),))),
)
else:
# For previous versions of scipy, this was possible through a dedicated
# metric (deprecated in 1.6 and removed in 1.8).
METRICS_DEFAULT_PARAMS.append(
("wminkowski", dict(p=(1, 1.5, 3), w=(rng.random_sample(d),))),
)
# TODO: Remove filterwarnings in 1.3 when wminkowski is removed
@pytest.mark.filterwarnings("ignore:WMinkowskiDistance:FutureWarning:sklearn")
@pytest.mark.parametrize(
"metric_param_grid", METRICS_DEFAULT_PARAMS, ids=lambda params: params[0]
)
@pytest.mark.parametrize("X, Y", [(X64, Y64), (X32, Y32), (X_mmap, Y_mmap)])
def test_cdist(metric_param_grid, X, Y):
DistanceMetricInterface = (
DistanceMetric if X.dtype == Y.dtype == np.float64 else DistanceMetric32
)
metric, param_grid = metric_param_grid
keys = param_grid.keys()
X_csr, Y_csr = sp.csr_matrix(X), sp.csr_matrix(Y)
for vals in itertools.product(*param_grid.values()):
kwargs = dict(zip(keys, vals))
rtol_dict = {}
if metric == "mahalanobis" and X.dtype == np.float32:
# Computation of mahalanobis differs between
# the scipy and scikit-learn implementation.
# Hence, we increase the relative tolerance.
# TODO: Inspect slight numerical discrepancy
# with scipy
rtol_dict = {"rtol": 1e-6}
if metric == "wminkowski":
# wminkoski is deprecated in SciPy 1.6.0 and removed in 1.8.0
WarningToExpect = None
if sp_version >= parse_version("1.6.0"):
WarningToExpect = DeprecationWarning
with pytest.warns(WarningToExpect):
D_scipy_cdist = cdist(X, Y, metric, **kwargs)
else:
D_scipy_cdist = cdist(X, Y, metric, **kwargs)
dm = DistanceMetricInterface.get_metric(metric, **kwargs)
# DistanceMetric.pairwise must be consistent for all
# combinations of formats in {sparse, dense}.
D_sklearn = dm.pairwise(X, Y)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn, D_scipy_cdist, **rtol_dict)
D_sklearn = dm.pairwise(X_csr, Y_csr)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn, D_scipy_cdist, **rtol_dict)
D_sklearn = dm.pairwise(X_csr, Y)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn, D_scipy_cdist, **rtol_dict)
D_sklearn = dm.pairwise(X, Y_csr)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn, D_scipy_cdist, **rtol_dict)
@pytest.mark.parametrize("metric", BOOL_METRICS)
@pytest.mark.parametrize(
"X_bool, Y_bool", [(X_bool, Y_bool), (X_bool_mmap, Y_bool_mmap)]
)
def test_cdist_bool_metric(metric, X_bool, Y_bool):
D_scipy_cdist = cdist(X_bool, Y_bool, metric)
dm = DistanceMetric.get_metric(metric)
D_sklearn = dm.pairwise(X_bool, Y_bool)
assert_allclose(D_sklearn, D_scipy_cdist)
# DistanceMetric.pairwise must be consistent
# on all combinations of format in {sparse, dense}².
X_bool_csr, Y_bool_csr = sp.csr_matrix(X_bool), sp.csr_matrix(Y_bool)
D_sklearn = dm.pairwise(X_bool, Y_bool)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn, D_scipy_cdist)
D_sklearn = dm.pairwise(X_bool_csr, Y_bool_csr)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn, D_scipy_cdist)
D_sklearn = dm.pairwise(X_bool, Y_bool_csr)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn, D_scipy_cdist)
D_sklearn = dm.pairwise(X_bool_csr, Y_bool)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn, D_scipy_cdist)
# TODO: Remove filterwarnings in 1.3 when wminkowski is removed
@pytest.mark.filterwarnings("ignore:WMinkowskiDistance:FutureWarning:sklearn")
@pytest.mark.parametrize(
"metric_param_grid", METRICS_DEFAULT_PARAMS, ids=lambda params: params[0]
)
@pytest.mark.parametrize("X", [X64, X32, X_mmap])
def test_pdist(metric_param_grid, X):
DistanceMetricInterface = (
DistanceMetric if X.dtype == np.float64 else DistanceMetric32
)
metric, param_grid = metric_param_grid
keys = param_grid.keys()
X_csr = sp.csr_matrix(X)
for vals in itertools.product(*param_grid.values()):
kwargs = dict(zip(keys, vals))
rtol_dict = {}
if metric == "mahalanobis" and X.dtype == np.float32:
# Computation of mahalanobis differs between
# the scipy and scikit-learn implementation.
# Hence, we increase the relative tolerance.
# TODO: Inspect slight numerical discrepancy
# with scipy
rtol_dict = {"rtol": 1e-6}
if metric == "wminkowski":
if sp_version >= parse_version("1.8.0"):
pytest.skip("wminkowski will be removed in SciPy 1.8.0")
# wminkoski is deprecated in SciPy 1.6.0 and removed in 1.8.0
ExceptionToAssert = None
if sp_version >= parse_version("1.6.0"):
ExceptionToAssert = DeprecationWarning
with pytest.warns(ExceptionToAssert):
D_scipy_pdist = cdist(X, X, metric, **kwargs)
else:
D_scipy_pdist = cdist(X, X, metric, **kwargs)
dm = DistanceMetricInterface.get_metric(metric, **kwargs)
D_sklearn = dm.pairwise(X)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn, D_scipy_pdist, **rtol_dict)
D_sklearn_csr = dm.pairwise(X_csr)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn_csr, D_scipy_pdist, **rtol_dict)
D_sklearn_csr = dm.pairwise(X_csr, X_csr)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn_csr, D_scipy_pdist, **rtol_dict)
# TODO: Remove filterwarnings in 1.3 when wminkowski is removed
@pytest.mark.filterwarnings("ignore:WMinkowskiDistance:FutureWarning:sklearn")
@pytest.mark.parametrize(
"metric_param_grid", METRICS_DEFAULT_PARAMS, ids=lambda params: params[0]
)
def test_distance_metrics_dtype_consistency(metric_param_grid):
# DistanceMetric must return similar distances for both float32 and float64
# input data.
metric, param_grid = metric_param_grid
keys = param_grid.keys()
# Choose rtol to make sure that this test is robust to changes in the random
# seed in the module-level test data generation code.
rtol = 1e-5
for vals in itertools.product(*param_grid.values()):
kwargs = dict(zip(keys, vals))
dm64 = DistanceMetric.get_metric(metric, **kwargs)
dm32 = DistanceMetric32.get_metric(metric, **kwargs)
D64 = dm64.pairwise(X64)
D32 = dm32.pairwise(X32)
# Both results are np.float64 dtype because the accumulation accross
# features is done in float64. However the input data and the element
# wise arithmetic operations are done in float32 so we can expect a
# small discrepancy.
assert D64.dtype == D32.dtype == np.float64
# assert_allclose introspects the dtype of the input arrays to decide
# which rtol value to use by default but in this case we know that D32
# is not computed with the same precision so we set rtol manually.
assert_allclose(D64, D32, rtol=rtol)
D64 = dm64.pairwise(X64, Y64)
D32 = dm32.pairwise(X32, Y32)
assert_allclose(D64, D32, rtol=rtol)
@pytest.mark.parametrize("metric", BOOL_METRICS)
@pytest.mark.parametrize("X_bool", [X_bool, X_bool_mmap])
def test_pdist_bool_metrics(metric, X_bool):
D_scipy_pdist = cdist(X_bool, X_bool, metric)
dm = DistanceMetric.get_metric(metric)
D_sklearn = dm.pairwise(X_bool)
assert_allclose(D_sklearn, D_scipy_pdist)
X_bool_csr = sp.csr_matrix(X_bool)
D_sklearn = dm.pairwise(X_bool_csr)
assert_allclose(D_sklearn, D_scipy_pdist)
# TODO: Remove filterwarnings in 1.3 when wminkowski is removed
@pytest.mark.filterwarnings("ignore:WMinkowskiDistance:FutureWarning:sklearn")
@pytest.mark.parametrize("writable_kwargs", [True, False])
@pytest.mark.parametrize(
"metric_param_grid", METRICS_DEFAULT_PARAMS, ids=lambda params: params[0]
)
@pytest.mark.parametrize("X", [X64, X32])
def test_pickle(writable_kwargs, metric_param_grid, X):
DistanceMetricInterface = (
DistanceMetric if X.dtype == np.float64 else DistanceMetric32
)
metric, param_grid = metric_param_grid
keys = param_grid.keys()
for vals in itertools.product(*param_grid.values()):
if any(isinstance(val, np.ndarray) for val in vals):
vals = copy.deepcopy(vals)
for val in vals:
if isinstance(val, np.ndarray):
val.setflags(write=writable_kwargs)
kwargs = dict(zip(keys, vals))
dm = DistanceMetricInterface.get_metric(metric, **kwargs)
D1 = dm.pairwise(X)
dm2 = pickle.loads(pickle.dumps(dm))
D2 = dm2.pairwise(X)
assert_allclose(D1, D2)
# TODO: Remove filterwarnings in 1.3 when wminkowski is removed
@pytest.mark.filterwarnings("ignore:WMinkowskiDistance:FutureWarning:sklearn")
@pytest.mark.parametrize("metric", BOOL_METRICS)
@pytest.mark.parametrize("X_bool", [X_bool, X_bool_mmap])
def test_pickle_bool_metrics(metric, X_bool):
dm = DistanceMetric.get_metric(metric)
D1 = dm.pairwise(X_bool)
dm2 = pickle.loads(pickle.dumps(dm))
D2 = dm2.pairwise(X_bool)
assert_allclose(D1, D2)
@pytest.mark.parametrize("X, Y", [(X64, Y64), (X32, Y32), (X_mmap, Y_mmap)])
def test_haversine_metric(X, Y):
DistanceMetricInterface = (
DistanceMetric if X.dtype == np.float64 else DistanceMetric32
)
# The Haversine DistanceMetric only works on 2 features.
X = np.asarray(X[:, :2])
Y = np.asarray(Y[:, :2])
X_csr, Y_csr = sp.csr_matrix(X), sp.csr_matrix(Y)
# Haversine is not supported by scipy.special.distance.{cdist,pdist}
# So we reimplement it to have a reference.
def haversine_slow(x1, x2):
return 2 * np.arcsin(
np.sqrt(
np.sin(0.5 * (x1[0] - x2[0])) ** 2
+ np.cos(x1[0]) * np.cos(x2[0]) * np.sin(0.5 * (x1[1] - x2[1])) ** 2
)
)
D_reference = np.zeros((X_csr.shape[0], Y_csr.shape[0]))
for i, xi in enumerate(X):
for j, yj in enumerate(Y):
D_reference[i, j] = haversine_slow(xi, yj)
haversine = DistanceMetricInterface.get_metric("haversine")
D_sklearn = haversine.pairwise(X, Y)
assert_allclose(
haversine.dist_to_rdist(D_sklearn), np.sin(0.5 * D_reference) ** 2, rtol=1e-6
)
assert_allclose(D_sklearn, D_reference)
D_sklearn = haversine.pairwise(X_csr, Y_csr)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn, D_reference)
D_sklearn = haversine.pairwise(X_csr, Y)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn, D_reference)
D_sklearn = haversine.pairwise(X, Y_csr)
assert D_sklearn.flags.c_contiguous
assert_allclose(D_sklearn, D_reference)
def test_pyfunc_metric():
X = np.random.random((10, 3))
euclidean = DistanceMetric.get_metric("euclidean")
pyfunc = DistanceMetric.get_metric("pyfunc", func=dist_func, p=2)
# Check if both callable metric and predefined metric initialized
# DistanceMetric object is picklable
euclidean_pkl = pickle.loads(pickle.dumps(euclidean))
pyfunc_pkl = pickle.loads(pickle.dumps(pyfunc))
D1 = euclidean.pairwise(X)
D2 = pyfunc.pairwise(X)
D1_pkl = euclidean_pkl.pairwise(X)
D2_pkl = pyfunc_pkl.pairwise(X)
assert_allclose(D1, D2)
assert_allclose(D1_pkl, D2_pkl)
def test_input_data_size():
# Regression test for #6288
# Previously, a metric requiring a particular input dimension would fail
def custom_metric(x, y):
assert x.shape[0] == 3
return np.sum((x - y) ** 2)
rng = check_random_state(0)
X = rng.rand(10, 3)
pyfunc = DistanceMetric.get_metric("pyfunc", func=custom_metric)
eucl = DistanceMetric.get_metric("euclidean")
assert_allclose(pyfunc.pairwise(X), eucl.pairwise(X) ** 2)
# TODO: Remove filterwarnings in 1.3 when wminkowski is removed
@pytest.mark.filterwarnings("ignore:WMinkowskiDistance:FutureWarning:sklearn")
def test_readonly_kwargs():
# Non-regression test for:
# https://github.com/scikit-learn/scikit-learn/issues/21685
rng = check_random_state(0)
weights = rng.rand(100)
VI = rng.rand(10, 10)
weights.setflags(write=False)
VI.setflags(write=False)
# Those distances metrics have to support readonly buffers.
DistanceMetric.get_metric("seuclidean", V=weights)
DistanceMetric.get_metric("wminkowski", p=1, w=weights)
DistanceMetric.get_metric("mahalanobis", VI=VI)
@pytest.mark.parametrize(
"w, err_type, err_msg",
[
(np.array([1, 1.5, -13]), ValueError, "w cannot contain negative weights"),
(np.array([1, 1.5, np.nan]), ValueError, "w contains NaN"),
(
sp.csr_matrix([1, 1.5, 1]),
TypeError,
"A sparse matrix was passed, but dense data is required",
),
(np.array(["a", "b", "c"]), ValueError, "could not convert string to float"),
(np.array([]), ValueError, "a minimum of 1 is required"),
],
)
def test_minkowski_metric_validate_weights_values(w, err_type, err_msg):
with pytest.raises(err_type, match=err_msg):
DistanceMetric.get_metric("minkowski", p=3, w=w)
def test_minkowski_metric_validate_weights_size():
w2 = rng.random_sample(d + 1)
dm = DistanceMetric.get_metric("minkowski", p=3, w=w2)
msg = (
"MinkowskiDistance: the size of w must match "
f"the number of features \\({X64.shape[1]}\\). "
f"Currently len\\(w\\)={w2.shape[0]}."
)
with pytest.raises(ValueError, match=msg):
dm.pairwise(X64, Y64)
# TODO: Remove in 1.3 when wminkowski is removed
def test_wminkowski_deprecated():
w = rng.random_sample(d)
msg = "WMinkowskiDistance is deprecated in version 1.1"
with pytest.warns(FutureWarning, match=msg):
DistanceMetric.get_metric("wminkowski", p=3, w=w)
# TODO: Remove in 1.3 when wminkowski is removed
@pytest.mark.filterwarnings("ignore:WMinkowskiDistance:FutureWarning:sklearn")
@pytest.mark.parametrize("p", [1, 1.5, 3])
def test_wminkowski_minkowski_equivalence(p):
w = rng.random_sample(d)
# Weights are rescaled for consistency w.r.t scipy 1.8 refactoring of 'minkowski'
dm_wmks = DistanceMetric.get_metric("wminkowski", p=p, w=(w) ** (1 / p))
dm_mks = DistanceMetric.get_metric("minkowski", p=p, w=w)
D_wmks = dm_wmks.pairwise(X64, Y64)
D_mks = dm_mks.pairwise(X64, Y64)
assert_allclose(D_wmks, D_mks)