@Override public double diffusionDiscretization(final StochasticProcess1D sp,final double t0,final double x0,final double dt){
  return sp.diffusion(t0,x0) * Math.sqrt(dt);
}

@ Override public double diffusionDiscretization ( final StochasticProcess1D sp , final double t0 , final double x0 , final double dt ) { return sp . diffusion ( t0 , x0 ) * Math . sqrt ( dt ) ; }
returns an approximation of the diffusion defined as < p > \ sigma ( t_0 , x_0 ) \ sqrt \ delta t } }
