pure subroutine fcn(beta, xplusd, ifixb, ifixx, ideval, f, fjacb, fjacd, istop)
!! User-supplied subroutine for evaluating the model.
integer, intent(in) :: ideval, ifixb(:), ifixx(:, :)
real(kind=wp), intent(in) :: beta(:), xplusd(:, :)
real(kind=wp), intent(out) :: f(:, :), fjacb(:, :, :), fjacd(:, :, :)
integer, intent(out) :: istop
! Local variables
real(kind=wp) :: uout
integer :: i
istop = 0
fjacb = zero
fjacd = zero
if (mod(ideval, 10) >= 1) then
do i = 1, ubound(f, 1)
f(i, 1) = 1440.0_wp
call mpf(uout, xplusd(i, 1), beta(1), beta(2), beta(3), zero, f(i, 1), xplusd(i, 1)/2)
end do
end if
end subroutine fcn