Libtool interface number history (the "c" in [c:r:a] of - 0 Legacy interface number for all releases prior to 2014.06 - 1 Incompatible API change. Most subroutines were converted into functions returning a success flag. Previously, the library called exit() on error conditions. The state of release 2014.06.001 defines this interface - 2 Incompatible API change. The routine for ELPA 2 real case takes an optional argument, defining whether QR decomposition is used or not The state of release 2015.02.001 defines this interface - 3 Incompatible API change. C Functions are added to provide an C interface. The subroutine "get_elpa_row_col_comms" has been converted to a function which returns an error code. The state of release 2015.02.002 defines this interface - 4 Incompatible API change. The Fortran versions of the library functions return a logical indicating success or failure. The C versions of the library functions return an integer {0,1} for success and failure. Some interface need an extra argument, specifying the number of matrix columns (see the documentation)