On Monday, 6 October 2014 03:00:03 UTC+2, Waldek Hebisch wrote:
>
> Right. I will commit the change. What name should I use in
> attribution line (email header just gives kfp, but we normally
> use full name)?
>
For whatever reason the header showed the nickname - strangely enough, only
for this group. Now I changed the local settings. Nevertheless, there is
really no need for attribution and it's only a typo anyway.
> Furthermore, neither of the examples (in *the* *book, help*) to
*CliffordAlgebra
> > *work anymore. One has to omit *quadraticForm *in the consturctors.
>
> Well, the examples in .htex files were updated. Once book is
> regenerated from .htex files this (and several other things)
> will propagate to book. IIUC correctly help files were
> obtained via manual editing, unless somebody volunteers to
> update them (or better, creates automatic procedure to
> propagate material from .htex to them) they will stay as is.
>
I've just 'discovered' http://fricas.github.io/book.pdf and I have to
apologize. It's fixed there! My compliments to Ralf, the documentation
project made considerable progress.
> > Finally, what's your opinion to the following matter?
> >
> > Extending DeRhamComplex with some functions like scalar product and
> Hodge
> > dual with respect to some metric g, what would be preferable: to include
> a
> > (set-able) default g into the domain or to give it as a parameter?
> >
> > For instance, in the first case one had to write
> >
> > setMetric([...]), dot(a,b), hodgeStar(a)
> >
> > or othewise
> >
> > dot(g,a,b), hodgeStar(g,a) ?
> >
>
> IMO parameter is better. If there is strong desire to avoid
> giving parameter on each use, then we can create extra domain
> having g as domain parameter. Then all forms from this domain
> will use the same g.
>
>
I think so too, it's more flexible. The DERHAM domain is a very clever
implementation by Larry A. Lambe and IMO has great potential. However, to
do some serious calculations in Physics (e.g. SR,GR,FT) or DiffG one needs
some (few) additional functionality. For the ortogonal case (i.e. diagonal
g) I did with about 20 lines of additional code, while the general case
(nondegenerate symmetric g) needs some more effort. Would it be worthwile?
Another point: in the description the (imo excellent) book of H. Flanders
is mentioned in which the Hodge dual is defined as a/\b=<*a,b> vol, whereas
nowadays a/\*b=<a,b>vol is prevailing. Is there any argument not to choose
the latter?
Kurt
> --
> Waldek Hebisch
> [email protected] <javascript:>
>
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