Re: Problem with log function - Intel fortran compiler under Linux

On Oct 4, 2:35?pm, Arjen Markus <arjen.mar...@xxxxxxxxxx> wrote:
Hello,

we are experiencing a rather nasty problem with the Intel Fortran
compiler under Linux
(version 9.0). The program is big and so far we have not been able to
trim the code
so that a moderately sized program displays the problem too.

The point is this:

The first application of the log function on double precision reals
causes
an NaN (while the argument is a perfectly acceptable value of about
0.6).

If we add a dummy statement like:

aa =log(r)

as one of the first statements, the value of aa becomes NaN and some
later computations
succeed. (NaNs occur at a different positions).

Here is some more information:

Intel Fortran: 9.0
Linux: Red Hat Enterprise Linux, ES release 4.

Has anyone encounter similar problems? Does anyone know how to solve
this problem?

Regards,

Arjen

It might be worth inserting your own LOG function, just to see if
anything interesting happens. If my algebra is correct:
log(x) = exp(-1.0) * log10(x)
might be a good place to start.

Dave Flower

.

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