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"""
Simple example datasets
"""
# Author: Remi Flamary <remi.flamary@unice.fr>
#
# License: MIT License
import numpy as np
import scipy as sp
from .utils import check_random_state, deprecated
def make_1D_gauss(n, m, s):
"""return a 1D histogram for a gaussian distribution (n bins, mean m and std s)
Parameters
----------
n : int
number of bins in the histogram
m : float
mean value of the gaussian distribution
s : float
standard deviaton of the gaussian distribution
Returns
-------
h : ndarray (n,)
1D histogram for a gaussian distribution
"""
x = np.arange(n, dtype=np.float64)
h = np.exp(-(x - m) ** 2 / (2 * s ** 2))
return h / h.sum()
@deprecated()
def get_1D_gauss(n, m, sigma):
""" Deprecated see make_1D_gauss """
return make_1D_gauss(n, m, sigma)
def make_2D_samples_gauss(n, m, sigma, random_state=None):
"""Return n samples drawn from 2D gaussian N(m,sigma)
Parameters
----------
n : int
number of samples to make
m : ndarray, shape (2,)
mean value of the gaussian distribution
sigma : ndarray, shape (2, 2)
covariance matrix of the gaussian distribution
random_state : int, RandomState instance or None, optional (default=None)
If int, random_state is the seed used by the random number generator;
If RandomState instance, random_state is the random number generator;
If None, the random number generator is the RandomState instance used
by `np.random`.
Returns
-------
X : ndarray, shape (n, 2)
n samples drawn from N(m, sigma).
"""
generator = check_random_state(random_state)
if np.isscalar(sigma):
sigma = np.array([sigma, ])
if len(sigma) > 1:
P = sp.linalg.sqrtm(sigma)
res = generator.randn(n, 2).dot(P) + m
else:
res = generator.randn(n, 2) * np.sqrt(sigma) + m
return res
@deprecated()
def get_2D_samples_gauss(n, m, sigma, random_state=None):
""" Deprecated see make_2D_samples_gauss """
return make_2D_samples_gauss(n, m, sigma, random_state=None)
def make_data_classif(dataset, n, nz=.5, theta=0, p=.5, random_state=None, **kwargs):
"""Dataset generation for classification problems
Parameters
----------
dataset : str
type of classification problem (see code)
n : int
number of training samples
nz : float
noise level (>0)
p : float
proportion of one class in the binary setting
random_state : int, RandomState instance or None, optional (default=None)
If int, random_state is the seed used by the random number generator;
If RandomState instance, random_state is the random number generator;
If None, the random number generator is the RandomState instance used
by `np.random`.
Returns
-------
X : ndarray, shape (n, d)
n observation of size d
y : ndarray, shape (n,)
labels of the samples.
"""
generator = check_random_state(random_state)
if dataset.lower() == '3gauss':
y = np.floor((np.arange(n) * 1.0 / n * 3)) + 1
x = np.zeros((n, 2))
# class 1
x[y == 1, 0] = -1.
x[y == 1, 1] = -1.
x[y == 2, 0] = -1.
x[y == 2, 1] = 1.
x[y == 3, 0] = 1.
x[y == 3, 1] = 0
x[y != 3, :] += 1.5 * nz * generator.randn(sum(y != 3), 2)
x[y == 3, :] += 2 * nz * generator.randn(sum(y == 3), 2)
elif dataset.lower() == '3gauss2':
y = np.floor((np.arange(n) * 1.0 / n * 3)) + 1
x = np.zeros((n, 2))
y[y == 4] = 3
# class 1
x[y == 1, 0] = -2.
x[y == 1, 1] = -2.
x[y == 2, 0] = -2.
x[y == 2, 1] = 2.
x[y == 3, 0] = 2.
x[y == 3, 1] = 0
x[y != 3, :] += nz * generator.randn(sum(y != 3), 2)
x[y == 3, :] += 2 * nz * generator.randn(sum(y == 3), 2)
elif dataset.lower() == 'gaussrot':
rot = np.array(
[[np.cos(theta), np.sin(theta)], [-np.sin(theta), np.cos(theta)]])
m1 = np.array([-1, 1])
m2 = np.array([1, -1])
y = np.floor((np.arange(n) * 1.0 / n * 2)) + 1
n1 = np.sum(y == 1)
n2 = np.sum(y == 2)
x = np.zeros((n, 2))
x[y == 1, :] = make_2D_samples_gauss(n1, m1, nz, random_state=generator)
x[y == 2, :] = make_2D_samples_gauss(n2, m2, nz, random_state=generator)
x = x.dot(rot)
elif dataset.lower() == '2gauss_prop':
y = np.concatenate((np.ones(int(p * n)), np.zeros(int((1 - p) * n))))
x = np.hstack((0 * y[:, None] - 0, 1 - 2 * y[:, None])) + nz * np.random.randn(len(y), 2)
if ('bias' not in kwargs) and ('b' not in kwargs):
kwargs['bias'] = np.array([0, 2])
x[:, 0] += kwargs['bias'][0]
x[:, 1] += kwargs['bias'][1]
else:
x = np.array(0)
y = np.array(0)
print("unknown dataset")
return x, y.astype(int)
@deprecated()
def get_data_classif(dataset, n, nz=.5, theta=0, random_state=None, **kwargs):
""" Deprecated see make_data_classif """
return make_data_classif(dataset, n, nz=.5, theta=0, random_state=None, **kwargs)
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