dcKessler(x, t, x0, t0, theta, d, dx, dxx, s, sx, sxx,
log=FALSE)t0; see details.x of the
drift coefficient; see details.x^2 of the
drift coefficient; see details.x of the
diffusion coefficient; see details.x^2 of the
diffusion coefficient; see details.x. All the functions d, dx, dxx, dt, s, sx,
and sxx must be functions of t, x, and theta.