Thanks very much to all who have replied. I think I should follow Malcolm's advice, I should not use an f90 compiler to make a library of LAPACK (Version 3.0) routines, used by the LAPACK90 package. Because, the latest version of LAPACK contains routines that incorporate the F95 standard of using extended functions like DCONJG. Thanks very much, thanks Alois! Mahmood -- Mahmood Ahmad (MSc by Research Student) AMOR Group, Department of Informatics and Simulation (DOIS), RMCS, Cranfield University, Shrivenham, Swindon, Wilts., UK Tel: 00-44-01793-785889 Email: [log in to unmask] [log in to unmask] F77 Code Compiled by NAG F90 Compiler