g_V_vec function

Vectorization of the function g_V

It allows to use the integrand of the target functional to minimize as the argument of the function integrate.

g_V_vec(
  Y,
  lambda,
  delta,
  gamma,
  quant,
  sigma2,
  n,
  nreg = nreg,
  rel_tol = 1e-04
)