Function test3

* test function to predict points in a 3D coordinate system lying within the * sphere of radius 1 and centre at origin as +1 and others as -1. Note that * each point is defined by 3 values but we use 6 features. The function will * create random sample points for training and test purposes. * The sphere centred at origin and radius 1 is defined as: * \f$x^2+y^2+z^2=r^2=1\f$ and if the \f$r^2<