numpy nearest neighbour as matmuls.py

def unpool(x, repeat=False):
    s = x.shape
    if repeat:
        r = 1
    else:
        r = 0
    kernel_x = np.tile([1, r] + [0,0] * (s[1]), s[1])[:s[1]*s[1]*2].reshape(s[1], (s[1]*2))
    kernel_y = np.tile([1, r] + [0,0] * (s[0]), s[0])[:s[0]*s[0]*2].reshape(s[0], s[0]*2)
    return np.matmul(np.matmul(x, kernel_x).transpose(), kernel_y).transpose()