Re: small example, using complex variables in Ada

["J-P. Rosen" <rosen@adalog.fr>]

Stephen Leake a �crit :
>> -- gnatmake dft.adb
>> --
>> -- ./dft.exe
>> -- ( 6.00000E+00, 0.00000E+00)
>> -- (-1.50000E+00, 8.66026E-01)
>> -- (-1.50000E+00,-8.66025E-01)
>> -- $
>>
>> ======= FORTRAN code ===========
>> ! dtf.f90, compiled with GCC 4.3.4
>> ! under CYGWIN 1.7.5
>> ! gfortran -Wall dft.f90
>> ! ./a.exe
>> ! (  6.0000000    ,  0.0000000    )
>> ! ( -1.4999999    , 0.86602557    )
>> ! ( -1.5000005    ,-0.86602497    )
>> !
> 
> It would be good to explain the small differences here; something about
> how the floating point options are set, I suspect.
In Ada, the value is rounded to the requested accuracy (A.10.9(25)). In
Fortran, the machine value is printed.

> It would be good to state the theoretically correct answer; I hope it's
> 1.5, not 1.499... :).
Note that they are mathematically equal (with an inifinite number of 9s)
-- 
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           J-P. Rosen (rosen@adalog.fr)
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