Do not write top level VHDL entity

Directs the EDA Netlist Writer not to write the top-level entity definition into your VHDL Output File (.vho) Definition. The default setting generates a VHDL Output File (.vho)with both the top-level entity and architecture definition. You should enable this option if your test-bench defines your top-level entity, otherwise the simulation tool generates a warning because you have duplicate top-level entity definitions.