[Wien] How we calculate formation energy for a system

Dear All, i am using FP-LAPW calculation using WIEN2k for a Heusler system Fe2-xCoMnAl. i want to calculate the formation energy for the phase stability of system and find out which site it prefers Mn/Fe/Al site when Co atom is added. formation energy = total energy of Fe2-xCoMnAl -total energy

Re: [Wien] How we calculate formation energy for a system

Dear all, When we calculate the layer structre of P, we get the following erro : ** Error in Parallel LAPW1 ** LAPW1 STOPPED at Wed Apr 22 23:51:41 CST 2015 ** check ERROR FILES! Error in LAPW1 Cholesky INFO =1 'SECLR4' - POTRF (Scalapack/LAPACK) failed. Error in LAPW1 Cholesky