Use Floating License Servers

I used to just set LM_LICENSE_FILE environment variable to all floating license servers for all EDA tools that I use. It had become unacceptably slow to start and run Matlab with LM_LICENSE_FILE (see this Matlab solution for more information), so I switched to use individual environment variable that each EDA vendor checks for licenses. Things have been working a lot better since I made the change. Below is a list of environment variables that tools I run on a regular basis check for a license. This is mainly for my own reference. Hopefully somebody else may also find it useful.

Mentor Graphics: MGLS_LICENSE_FILE
Matlab: MLM_LICENSE_FILE
Synposys: SNPSLMD_LICENSE_FILE
Xilinx: XILINXD_LICENSE_FILE

P.S.: Check AR11630 (http://www.xilinx.com/support/answers/11630.htm) for instructions on how to set up environment variables. My personal favorite tool for setting/editing environment variables is Rapid Environment Editor
P.P.S: Check other Cool Programs in My Toolbox

Ternary Adder with LUT6_2

Xilinx Virtex5 and newer FPGAs have 6-input look up tables with dual outputs (LUT6_2), which can be efficiently used to build ternary adders. The technique is described in details in US patent 7274211. Below is the circuit copied from the patent filing: