Set opt_level=3 as default value. The merger is called on each op-dag with this opt_level=3.
Set opt_level=3 as default value. The merger is called on each op-dag with this opt_level=3.

hewlettpackardlabs/opveclib,opveclib/opveclib,hewlettpackardlabs/opveclib,hewlettpackardlabs/opveclib,opveclib/opveclib,opveclib/opveclib