Re: A Level 2 query - X-X / you only
On 2013-07-03 15:01:29 -0700, Richard Fateman wrote:
> This is a philosophical question about identity of numbers.
I'd say that this is a language issue. If X stands for an interval
in the language, then the "optimization" is not allowed. If X
stands for a real number approximated/represented by an interval,
then the optimization is allowed.
And I think that making a decision based on the name of the variable
is a bad idea. If I write X = Y, X and Y having the same type, then
using either X or Y should have the same semantics (perhaps not the
same effect in practice, but the intent is to say the same thing).
But this is a language issue.
> Are 2 numbers the same if they occur in the same memory location?
> Are 2 numbers different if they occur in different memory locations, perhaps
> even in different computers?
Like the variable names, the memory location (or any similar idea)
shouldn't matter. Note that in ISO C, what defines a pointer is not
just the memory location and the pointed-to type, but according to
a recent defect report, also the history of how the pointer has been
computed.
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Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
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