6. Installing LAPACK Routines
Society for Industrial and Applied Mathematics eBooks · 1999
6.1 Points to NoteFor anyone who obtains the complete LAPACK package from netlib (see Chapter 1), a comprehensive installation guide is provided. We recommend installation of the complete package as the most convenient and reliable way to make LAPACK available.People who obtain copies of a few LAPACK routines from netlib need to be aware of the following points:1. Double precision complex routines (names beginning Z-) use a COMPLEX*16 data type. This is an extension to the Fortran 77 standard, but is provided by many Fortran compilers on machines where double precision computation is usual. The following related extensions are also used:• the intrinsic function DCONJG, with argument and result of type COMPLEX*16;• the intrinsic functions DBLE and DIMAG, with COMPLEX*16 argument and DOUBLE PRECISION result, returning the real and imaginary parts, respectively;• the intrinsic function DCMPLX, with DOUBLE PRECISION argument(s) and COMPLEX*16 result;• COMPLEX*16 constants, formed from a pair of double precision constants in parentheses.Some compilers provide DOUBLE COMPLEX as an alternative to COMPLEX*16, and an intrinsic function DREAL instead of DBLE to return the real part of a COMPLEX*16 argument. If the compiler does not accept the constructs used in LAPACK, the installer will have to modify the code: for example, globally change COMPLEX*16 to DOUBLE COMPLEX, or selectively change DBLE to DREAL.