Glas List: Re: [glas] Concept C++ [was Re: back to business}

From: Karl Meerbergen (karl.meerbergen_at_[hidden])
Date: 2006-11-23 02:39:02

Peter,

One question that is on my mind for a while now is the following one:
the mathematical definition of e.g. magma is clear. When do two types
belong to the same magma? E.g. int + double is an operation between
different types but they belong to double. Is there a mechanism in your
concepts that takes care of this?

Another examples is vector<double> v, w ;
The expression v+w returns e.g.
add_vector< vector<double>, vector<double> >,
which is only evaluated at assignment, e.g. x=v+w.
Do you deal with this returntype in your concepts? I think this would be
very helpful.

Thanks,

Karl

On Wed, 2006-11-22 at 10:38 -0500, Peter Gottschling wrote:
> Well, I used ConceptGCC many times and it works quite well now.  The 
> fundamental concepts on the GLAS list, like ring and group, are 
> implemented with concepts now and compiled with ConceptGCC. I published 
> the results as technical report:
> 
> http://www.cs.indiana.edu/cgi-bin/techreports/TRNNN.cgi?trnum=TR638
> 
> There is amongst others an example to compute the power function with 
> regard to an arbitrary binary function. There are different algorithms 
> for magma, semi-group, monoid and groups. The concept compiler 
> dispatches to the most appropriate.
> 
> In another paper still pending I did performance experiments and it 
> showed that the performance is the same as with gcc without concepts.
> 
> There were occasionally some minor problems with ConceptGCC but Doug 
> fixed most of them in the meantime.  That said, the compiler is not in 
> perfect production mode yet but it is already extremely useful for 
> working with concepts.
> 
> Cheers,
> Peter
> 
> On 22.11.2006, at 08:52, Ian McCulloch wrote:
> 
> >
> > On Wed, 22 Nov 2006, Karl Meerbergen wrote:
> >
> >> I think we should consider this. Is concept-gcc stable now?
> >
> > I think it is, although last time I checked there were some issues with
> > compile times that ought to go away in the final version.  Aside from
> > spending a few hours reading the proposal, I have never used concept 
> > gcc.
> > Maybe someone else on this list has?  My impression was though, it 
> > would
> > be the killer feature for linear algebra libs.
> >
> > Cheers,
> > Ian
> >
> >
> >>
> >>
> >> On Wed, 2006-11-22 at 14:36 +0100, Ian McCulloch wrote:
> >>> Hi Karl, Toon,
> >>>
> >>> Have you considered using Concept-GCC ?
> >>> http://www.generic-programming.org/languages/conceptcpp/
> >>>
> >>> Ian
> >>>
> >>> _______________________________________________
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> >> -- 
> >> Karl Meerbergen
> >> Katholieke Universiteit Leuven
> >> Department of Computer Science
> >>
> >> E-mail: karl.meerbergen_at_[hidden]
> >> URL   : http://www.cs.kuleuven.be/cwis/research/nalag/
> >> Phone : [phone] (secretary)
> >> Fax   : [phone]
> >>
> >> _______________________________________________
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> >>
> >>
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> ------------
> Peter Gottschling, Ph.D.
> Research Associate
> Open Systems Laboratory
> Indiana University
> 135 Lindley Hall
> Bloomington, IN 47405
> Tel.: [phone]   Fax: [phone]
> http://www.osl.iu.edu/~pgottsch
> 
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-- 
Karl Meerbergen
Katholieke Universiteit Leuven
Department of Computer Science
E-mail: karl.meerbergen_at_[hidden]
URL   : http://www.cs.kuleuven.be/cwis/research/nalag/
Phone : [phone] (secretary)
Fax   : [phone]