Hi,friends

I would like to know how to detect NaN's in Fortran code. I want the code to stop at the first NaN when something gets weird and then step into.

Thanks,

Wen

Look up "exception handling" in the documentation for your compiler. The implementation will vary from compiler to compiler.

Hi, if you are using F77, the following would be useful for debugging:

f77 -g -ftrap=common -O3 file.f -o file.e

dbx file.e

catch fpe

run

You will find out which value is zero !

Regards

Li

If you use digital Visual Fortran, you can set the entry of floating point exception to 1 instead of 3 on project/setting/fortran/floating point.

Good luck!

Hi, there:

I have 2 methods:

1. To use Function IsNaN(*)

* real

it gives you a logical type

2. Do it my own way

Check if (a + 1.0) .eq. a , only NaNs will give

you a .true. answer

Good luck!