Re: single to double conversion

[Craig Powers <enigma at hal-pc dot org>]

Brian Barnes wrote:
> On Tue, 26 Sep 2006, Craig Powers wrote:
>
>
> > promotion from integer to floating point may occur later than a naive
> > user would expect.
>
> I believe if promotion from integer to real occured so late in a simple
> calculation that it created a mathematically incorrect result, that should
> be regarded as a bug in gfortran.  It's quite possible that the developers
> disagree with me on this, but I'm just speaking as a chemist who is trying
> to get some work done in Fortran.  I've used g77 for years and not had a
> problem of this sort.  I haven't encountered a problem like that in
> gfortran either, so I hope nothing has changed.

I'm not sure what you mean by "mathematically incorrect".  I was 
referring to something of the nature of,

    REAL bar

    ! ...

    bar = 1/3 + 2.5

where I expect the result of 1/3 will be 0, because promotion to 
floating point will not happen until the addition with 2.5.