code: function find_mdw_colw(collw) {
  	var delta = Math.abs(collw - cycle_width(collw)), _MDW = MDW;
  	if(delta > 0.005) for(MDW=MIN_MDW; MDW<MAX_MDW; ++MDW) if(Math.abs(collw - cycle_width(collw)) <= delta) { delta = Math.abs(collw - cycle_width(collw)); _MDW = MDW; }
  	MDW = _MDW;
  }
docs: /* XLSX/XLSB/XLS specify width in units of MDW