generate_nonlinear_data.py

import numpy as np
import random


def generate_chess(size1, size2, y_type, chesize, fli, frac=0.25, seed=10):
    """Generates highly non-linear, chessboard like data."""
    np.random.seed(seed)
    random.seed(seed)
    X1 = chesize*np.random.random(size1)
    X2 = chesize*np.random.random(size2)
    paircount = int(frac*size1*size2)
    rowind = np.random.randint(0, size1, paircount)
    colind = np.random.randint(0, size2, paircount)
    #foo = rowind + colind
    #I = np.argsort(foo)
    I = np.argsort(colind)
    rowind = rowind[I]
    colind = colind[I]
    Y = []

    if y_type == 2:
        kertoimet = []

    for rind, cind in zip(rowind, colind):
        y1 = int(X1[rind])%2
        y2 = int(X2[cind])%2

        if y_type == 2:
            kertoimet.append(y1 * y2)

        y = np.logical_xor(y1, y2)

        if fli == 0.0:
                Y.append(y)
        else:
            if random.random() > fli:
                Y.append(y)
            else:
                Y.append(y == False)

    # Y is currently filled with ones and zeros and we want the labels to be -1 or 1
    Y = 2.*np.array(Y)-1

    if y_type == 2:
        for j in range(len(kertoimet)):
            kertoimet[j] * Y[j]

    X1 = X1.reshape(size1, 1)
    X2 = X2.reshape(size2, 1)
    rowind = np.array(rowind, dtype=np.int32)
    colind = np.array(colind, dtype=np.int32)

    return X1, X2, rowind, colind, Y