Re: ieee on Windows problem

[Brad Finney <Brad dot Finney at humboldt dot edu>]

On 6/30/2014 12:31 PM, FX wrote:
> > OK, all of the test programs EXCEPT ieee_2.f90 execute successfully.
>
> Nice!
>
>
> > ieee_2.f90 crashes on the following line
> >   if (ieee_class(ieee_logb(-sx1)) /= ieee_positive_inf) call abort
>
> Can you tell me what the following program outputs? (compiled with no optimization and the IEEE flags)
>
>    use, intrinsic :: ieee_arithmetic
>    real :: sx1
>
>    sx1 = ieee_value(sx1, ieee_positive_inf)
>    print *, sx1, -sx1
>    print *, ieee_logb(sx1), ieee_logb(-sx1)
>    print *, exponent(sx1), exponent(-sx1)
>
>    end
>
> For me, on x86_64-apple-darwin, it shows:
>
>           Infinity        -Infinity
>           Infinity         Infinity
>             0           0
>
> which is, by my reading, correct for IEEE_LOGB, but incorrect for the pre-existing EXPONENT intrinsic ("If X is an IEEE infinity or NaN, the result has the value HUGE(0)”).
>
>
> FX


D:\fortran\ieee>a
         Infinity        -Infinity
         Infinity        -Infinity
          -1          -1
--
Brad Finney
Professor, Environmental Resources Engineering
Humboldt State University, Arcata, CA  95521
707.826.3918