def load(n_samples=10000, n_features=10, n_manifolds=10, seed=0):
"""Generate a multi spiral bands dataset randomly in many dims
The resulting dataset hence holds a set of instrically 2 dim manifolds
(spiralling band) embedded in an arbitrarly higher dimensional space.
Parameters
----------
n_samples : number of sample to generate
n_features : total number of dimension
n_manifolds : number of manifolds to generate
seed : reproducible pseudo random dataset generation
Returns
-------
data : an array of shape (n_samples, n_features) embedding the generated
hyber-swissroll
manifolds : an array of size (n_manifolds, n_samples / n_manifolds, 2)
that contains the unrolled manifolds
t : the array of parameters value which is the intrinsic dimension
common to all manifolds
"""
assert n_features >= 3
rng = np.random.RandomState(seed)
data = []
manifolds = []
for i in xrange(n_manifolds):
n_samples_m = n_samples / n_manifolds
if i < n_samples % n_manifolds:
n_samples_m += 1
data_m, manifold_m = load_one(
n_samples=n_samples_m,
n_features=n_features,
n_turns=rng.uniform(0.2, 2),
radius=rng.uniform(0.5, 2),
hole=rng.uniform() > 0.5,
rotate=False,
seed=seed,
)
data_m[:, 0] += rng.uniform(-2, 2)
data_m[:, 1] += rng.uniform(-2, 2)
data_m[:, 2] += rng.uniform(-2, 2)
data_m = random_rotate(data_m, rng)
data.append(data_m[:, rng.permutation(n_features)])
manifolds.append(manifold_m)
data = random_rotate(np.vstack(data), rng)
t_without_holes = np.hstack([m[:, 0] for m in manifolds])
return data, manifolds, t_without_holes
def load(n_samples=1000, n_features=3, rotate=True, n_turns=1.5, seed=0,
radius=1.0, hole=False):
"""Generate a single spiral band dataset on the first 2 dims
The third dim is fill uniformly. The remaining dims are left to zeros
(before random rotation).
The resulting dataset hence holds a instrically 2 dim manifold (a spiralling
band) embedded in an arbitrarly higher dimensional space.
Parameters
----------
n_samples : number of sample to generate
n_features : total number of dimension including the first two that include
the actual spiral data (when not rotated)
n_turns : number of rotations (times 2 pi) for the spiral manifold
rotate : boolean flag to rotate randomly the spiral iteratively on all
dimensions
hole : boolean flag to dig a rectangular hole in the middle of the roll
band
Returns
-------
data : an array of shape (n_samples, n_features) embedding the generated
hyber-swissroll
manifold : an array of size (n_samples, 2) that contains the unrolled
manifold
NB: if hole is True, the samples in the hole are removed hence the
dimensions of the results will be smaller that n_samples
"""
assert n_features >= 3
rng = np.random.RandomState(seed)
t = rng.uniform(low=0, high=1, size=n_samples)
data = np.zeros((n_samples, n_features))
# generate the 2D spiral data driven by a 1d parameter t
max_rot = n_turns * 2 * np.pi
data[:, 0] = radius = t * np.cos(t * max_rot)
data[:, 1] = radius = t * np.sin(t * max_rot)
# fill the third dim with the uniform band of width [-1, 1]
data[:, 2] = rng.uniform(-1, 1.0, n_samples)
# copy the manifold data before performing the rotation
manifold = np.vstack((t * 2 - 1, data[:, 2])).T.copy()
if hole:
z = data[:, 2]
indices = np.where(((0.3 > t) | (0.7 < t)) | ((-0.3 > z) | (0.3 < z)))
data = data[indices]
manifold = manifold[indices]
if rotate:
data = random_rotate(data, rng)
return data, manifold
