subroutine run_optimizer (hit_limit)

use cesrv_struct
use cesrv_interface
use super_universe_com

implicit none

real(rp) merit0, a_lambda

integer i, i_cyc

logical, optional :: hit_limit
logical finished, limited, at_limit

!

call dmerit_calc ('reinit')
call merit_calc(merit0)
print *, 'Initial merit:', merit0

if (logic%engine == "FLETCHER-REEVES") then
  print *, '   Loop      Merit   Cycles_used   Calls/Cycle'
elseif (logic%engine == "LEVENBERG-MARQUARDT") then
  print *, '   Loop      Merit  A_lambda'
endif

logic%opt_running = .true.  ! for minimal computations
at_limit = .false.

do i = 1, logic%opt_loops

  i_cyc = logic%opt_cycles
  logic%n_1dim_calls = 0

  if (logic%engine == "FLETCHER-REEVES") then
    call fletcher_reeves(i, i_cyc, finished, super%u_(1))
    call limit_calc (limited)
    call merit_calc(merit0)
    print '(i5, f14.3, 2i14)', i, merit0, i_cyc, logic%n_1dim_calls/i_cyc
  elseif (logic%engine == "LEVENBERG-MARQUARDT") then
    call marquardt(i, a_lambda, finished, super%u_(1), limited)
    call merit_calc(merit0)
    print '(i5, f14.3, 1pe10.2)', i, merit0, a_lambda
  else
    print *, 'ERROR: THIS ENGINE NOT YET IMPLIMENTED: ', logic%engine
  endif

  if (limited) at_limit = .true.
  if (finished) exit

enddo

logic%opt_running = .false.
call merit_calc(merit0)
if (present(hit_limit)) hit_limit = at_limit

end subroutine