dinvwt Subroutine

pure subroutine dinvwt(neq, wt, ierr)
!! This subroutine checks the error weight vector `wt` for components that are less
!! or equal to 0, and if none are found, it inverts `wt` in place. This replaces
!! division operations with multiplications in all norm evaluations.

   use daskr_kinds, only: rk, zero
   implicit none

   integer, intent(in) :: neq
      !! Problem size.
   real(rk), intent(inout) :: wt(neq)
      !! Weights for error control.
   integer, intent(out) :: ierr
      !! Completion flag.
      !! `0`: all elements were found positive.
      !! `i > 0`: `w(i)` is the first non positive weight.

   integer :: i

   do i = 1, neq
      if (wt(i) .le. zero) then
         ierr = i
         return
      end if
   end do

   wt = 1/wt
   ierr = 0

end subroutine dinvwt