The runatom.x program generates pseudopotentials (*.uspp files) in a binary format using "unformatted" fortran write statements. Unfortunately, different computers may expect unformatted datafiles to be in different internal formats. This may cause problems when trying to move *.uspp files between different computer systems. The most standard format is the IEEE one; it is used by default on most Unix and Linux systems. However, on some systems (such as DEC/COMPAQ compilers for Alphas) a different default may be in place. In such cases, it is recommended to choose compiler options that will force reading and writing in IEEE format. See the Source/Makefile header for hints on how to do this. However, if this proves problematic for one reason or another, then the 'reform' program in the Utils/ directory can be used to convert the pseudopotential datafiles from unformatted to formatted form and vice versa. See Utils/README. (Note: if using ftp to transfer *.uspp files between computers, be sure to set the 'binary' option.) Finally, the Utils directory also contains a program read_uspp.f. This is a dummy program that does nothing but read in a binary pseudopotential file of version 732 or later. It could form the basis for other conversion programs, or simply serve as a concise summary of the pseudopotential file format. David Vanderbilt July 2002 ------------------------------------------------------------------------ Prof. David Vanderbilt Phone: (732) 445-2514 Department of Physics and Astronomy Fax: (732) 445-4400 Rutgers University Email: dhv@physics.rutgers.edu 136 Frelinghuysen Road http://www.physics.rutgers.edu/~dhv Piscataway, NJ 08854-8019 USA ------------------------------------------------------------------------