Re: pseudoinverse

Raymond Toy <[email protected]> 22 Nov 2002 17:52:53 -0500
Newsgroups gmane.lisp.matlisp.user
Message-ID <[email protected]>
>>>>> "Michael" == Michael A Koerber <[email protected]> writes:

    Michael> I haven't studied this enough yet, but it appears that D1MACH.LISP is
    Michael> used via F2CL to provide MACH information to the FORTRAN routines in,
    Michael> e.g., TOMS.  D1MACH draws its information from the CL implimentation
    Michael> limits.  I don't know that this is the same as that produced by
    Michael> underlying FORTRAN compiler's treatement of D1MACH.F.  Unless it
    Michael> is the same, the numerically accuracy of the routines that rely
    Michael> on it could be impacted.  This is just a concern on my part, not 

Yes, this is true in general, but if LAPACK needs stuff from d1mach,
it's going to get it from the Fortran d1mach, not the Lisp d1mach.

There is a problem, however, because if there is such a thing for
LAPACK, it probably hasn't been tweaked at all so whatever those the
defaults are are getting used.

Ray