function [ncol,ncol_rank,ncol_hybrid,ncol_dem,ncol_scal] = ncol_from_flags(irank,ihybrid,idem,iscal)
  % [ncol,ncol_rank,ncol_hybrid,ncol_dem,ncol_scal] = ncol_from_flags(irank,ihybrid,idem,iscal)
  % Get number of columns from flags
  % Input
  %   irank           rank written?
  %   ihybrid         hybrid written?
  %   idem            DEM written?
  %   iscal           scalar written? (number of scalars)
  % Output
  %   ncol            total number of columns
  %   ncol_rank       number of columns (rank)
  %   ncol_hybrid     number of columns (hybrid)
  %   ncol_dem        number of columns (DEM)
  %   ncol_scal       number of columns (scalar)
  
  ncol_rank   = 0;
  ncol_hybrid = 0;
  ncol_dem    = 0;
  ncol_scal   = 0;
  if irank;   ncol_rank   = 1;       end
  if ihybrid; ncol_hybrid = 21;      end
  if idem;    ncol_dem    = 6;       end
  if iscal;   ncol_scal   = 2*iscal; end
  ncol = ncol_rank+ncol_hybrid+ncol_dem+ncol_scal;
end