! Module file: definemonitor_twin
!
! CNS module
! **********
!
! Authors: Axel Brunger and Paul Adams
!
! copyright Yale University
!
! Function:
!    Defines the monitor expression for hemihedrally twinned data
!
! Requirements:
!    Needs to be called within xray

module {definemonitor}
(
  &monitor="twin_lsq";    {string}
  &fobs=fobs;             {reciprocal space array}
  &fcalc=fcalc;           {reciprocal space array}
  &fpart=fpart;           {reciprocal space array}
  &phase=phase;           {reciprocal space array}
  &twin_oper=h,k,l;       {string}
  &twin_frac=0.0;         {real}
  &monitortype;           {string}
)

set message ? end
evaluate ($message_old=$result)
set echo ? end
evaluate ($echo_old=$result)
if ( $log_level = verbose ) then
  set echo=on message=normal end
else
  set echo=off message=off end
end if

checkversion 1.3

{- Twin residual -}
if ( &monitor = "twin_lsq" ) then

  monitor=(rvalue[overall](&fobs,(sqrt((1-&twin_frac)*abs(                  &fcalc+&fpart )^2 +
                                          &twin_frac *abs(remap[&twin_oper](&fcalc+&fpart))^2))))
  evaluate (&monitortype="R-value")

else
  
  display Monitor-error: unknown monitor definition, defaulting to residual

  monitor=(rvalue[overall](&fobs,(sqrt((1-&twin_frac)*abs(                  &fcalc+&fpart )^2 +
                                          &twin_frac *abs(remap[&twin_oper](&fcalc+&fpart))^2))))
  evaluate (&monitortype="R-value")

end if

set message=$message_old echo=$echo_old end