pure subroutine fcn(n, m, np, nq, ldn, ldm, ldnp, beta, xplusd, ifixb, ifixx, &
ldifx, ideval, f, fjacb, fjacd, istop)
!! User-supplied subroutine for evaluating the model.
integer, intent(in) :: ideval, ldifx, ldm, ldn, ldnp, m, n, np, nq
integer, intent(in) :: ifixb(np), ifixx(ldifx, m)
real(kind=wp), intent(in) :: beta(np), xplusd(ldn, m)
real(kind=wp), intent(out) :: f(ldn, nq), fjacb(ldn, ldnp, nq), fjacd(ldn, ldm, nq)
integer, intent(out) :: istop
! Local variables
integer :: i
! Check for unacceptable values for this problem
if (beta(1) .gt. zero) then
istop = 1
return
else
istop = 0
end if
! Compute predicted values
if (mod(ideval, 10) .ge. 1) then
do i = 1, nq
f(:, i) = beta(3)*(xplusd(:, 1) - beta(1))**2 + &
2*beta(4)*(xplusd(:, 1) - beta(1))*(xplusd(:, 2) - beta(2)) + &
beta(5)*(xplusd(:, 2) - beta(2))**2 - one
end do
end if
end subroutine fcn