DHTMLXGrid dhtmlxgrid_excell_math.js missing

I’m trying to do grid.groupBy(2,["#stat_max","#title","","#stat_total","","#cspan","#cspan","#cspan"]);
like showing here:

docs.dhtmlx.com/doku.php?id=dhtmlxgrid:grouping

But, in this part of documentation
docs.dhtmlx.com/doku.php?id=dhtm … th_in_grid

says that I need the file dhtmlxgrid_excell_math.js.

I have the version dhtmlxGrid v.2.6 Professional edition build 100722

and I can’t find this file here.

Where can I find this file ??

Sorry for inconvenience. You should include dhtmlxgrid_math.js file to your page.