{+ file: flip_friedels.inp +}
{+ directory: xtal_util +}
{+ description: Flip Friedel mates for all input arrays +}
{+ comment:
        This task file is useful only if the diffraction data were
        incorrectly indexed on a left handed basis system.  If the data
        are correctly indexed on a right handed basis system, the
        assignment of "F+" and "F-" is such that the experimental
        electron density map will show amino acids and helices with the
        correct hand.  Only if a left handed system was chosen (for 
        example if the sign of Y SCALE in Denzo was chosen incorrectly),
        the experimental electron density map will have the wrong hand.

        Refer to the CNS on-line tutorial for more information. +}

{+ authors: Ralf W. Grosse-Kunstleve and Paul D. Adams +}
{+ copyright: Yale University +}

{- Guidelines for using this file:
   - all strings must be quoted by double-quotes
   - logical variables (true/false) are not quoted
   - do not remove any evaluate statements from the file -}

{- begin block parameter definition -} define(

{====================== crystallographic data ========================}

{* space group *}
{* use International Table conventions with subscripts substituted
   by parenthesis *}
{===>} sg="P2(1)2(1)2(1)";

{* unit cell parameters in Angstroms and degrees *}
{+ table: rows=1 "cell" cols=6 "a" "b" "c" "alpha" "beta" "gamma" +}
{===>} a=65.508;
{===>} b=72.216;
{===>} c=45.035;
{===>} alpha=90;
{===>} beta=90;
{===>} gamma=90;

{========================= reflection file ===========================}

{* reflection file *}
{===>} reflection_infile="mbp_scale.hkl";

{========================== output options ===========================}

{* output file with flipped Friedel mates *}
{===>} reflection_outfile="flip_friedels.hkl";

{===========================================================================}
{         things below this line do not normally need to be changed         }
{===========================================================================}

 ) {- end block parameter definition -}

checkversion 1.3

evaluate ($log_level=quiet)

xray

   @CNS_XTALLIB:spacegroup.lib (sg=&sg;sgparam=$sgparam;)

   a=&a b=&b c=&c  alpha=&alpha beta=&beta gamma=&gamma

   reflection @@&reflection_infile end

   ANOMalous=?
   if ($result = false) then
     display ************************************************************
     display ERROR: NO ANOMALOUS SIGNAL IN FILE &file
     display ************************************************************
     display
     abort
   end if

   flip

end

set display=&reflection_outfile end

@CNS_XTALMODULE:write_hkl_header (sg=&STRIP%sg;
                                    sgparam=$sgparam;)

xray

   write reflection
     output=&reflection_outfile
   end

   set display=OUTPUT end

end

stop