def test_knn_graph_anisotropy():
k = 3
a = 13
n_pca = 20
anisotropy = 0.9
thresh = 1e-4
data_small = data[np.random.choice(len(data), len(data) // 2, replace=False)]
pca = PCA(n_pca, svd_solver="randomized", random_state=42).fit(data_small)
data_small_nu = pca.transform(data_small)
pdx = squareform(pdist(data_small_nu, metric="euclidean"))
knn_dist = np.partition(pdx, k, axis=1)[:, :k]
epsilon = np.max(knn_dist, axis=1)
weighted_pdx = (pdx.T / epsilon).T
K = np.exp(-1 * weighted_pdx ** a)
K[K < thresh] = 0
K = K + K.T
K = np.divide(K, 2)
d = K.sum(1)
W = K / (np.outer(d, d) ** anisotropy)
np.fill_diagonal(W, 0)
G = pygsp.graphs.Graph(W)
G2 = build_graph(
data_small,
n_pca=n_pca,
thresh=thresh,
decay=a,
knn=k - 1,
random_state=42,
use_pygsp=True,
anisotropy=anisotropy,
)
assert isinstance(G2, graphtools.graphs.kNNGraph)
assert G.N == G2.N
np.testing.assert_allclose(G.dw, G2.dw, atol=1e-14, rtol=1e-14)
np.testing.assert_allclose((G2.W - G.W).data, 0, atol=1e-14, rtol=1e-14)
def test_exact_graph_anisotropy():
k = 3
a = 13
n_pca = 20
anisotropy = 0.9
data_small = data[np.random.choice(len(data),
len(data) // 2,
replace=False)]
pca = PCA(n_pca, svd_solver="randomized", random_state=42).fit(data_small)
data_small_nu = pca.transform(data_small)
pdx = squareform(pdist(data_small_nu, metric="euclidean"))
knn_dist = np.partition(pdx, k, axis=1)[:, :k]
epsilon = np.max(knn_dist, axis=1)
weighted_pdx = (pdx.T / epsilon).T
K = np.exp(-1 * weighted_pdx**a)
K = K + K.T
K = np.divide(K, 2)
d = K.sum(1)
W = K / (np.outer(d, d)**anisotropy)
np.fill_diagonal(W, 0)
G = pygsp.graphs.Graph(W)
G2 = build_graph(
data_small,
thresh=0,
n_pca=n_pca,
decay=a,
knn=k - 1,
random_state=42,
use_pygsp=True,
anisotropy=anisotropy,
)
assert isinstance(G2, graphtools.graphs.TraditionalGraph)
assert G.N == G2.N
np.testing.assert_equal(G.dw, G2.dw)
assert (G2.W != G.W).sum() == 0
assert (G.W != G2.W).nnz == 0
with assert_raises_message(ValueError,
"Expected 0 <= anisotropy <= 1. Got -1"):
build_graph(
data_small,
thresh=0,
n_pca=n_pca,
decay=a,
knn=k - 1,
random_state=42,
use_pygsp=True,
anisotropy=-1,
)
with assert_raises_message(ValueError,
"Expected 0 <= anisotropy <= 1. Got 2"):
build_graph(
data_small,
thresh=0,
n_pca=n_pca,
decay=a,
knn=k - 1,
random_state=42,
use_pygsp=True,
anisotropy=2,
)
with assert_raises_message(ValueError,
"Expected 0 <= anisotropy <= 1. Got invalid"):
build_graph(
data_small,
thresh=0,
n_pca=n_pca,
decay=a,
knn=k - 1,
random_state=42,
use_pygsp=True,
anisotropy="invalid",
)