Hi,
On Jun 25, 9:05 am, Burcin Erocal <bur...@erocal.org> wrote:
> On Thu, 25 Jun 2009 13:22:46 +0200
>
> Stan Schymanski <schym...@gmail.com> wrote:
>
> > I have been asked to forward the below to the sage-devel list. Ticket
> > #6290 introduced a way to custom-define thelatexstyle of functions,
> > but it would be great if something similar was made possible for any
> > variable. Is there a way for this already? I used to do it in the
> > following way, but now I get an error message:
>
> > sage: var('hi kunsati delyui')
> > sage: hi._latex_ = lambda: 'h_i' # Matric suction
> > head in layer i (=pcapvec)
> > sage: kunsati._latex_ = lambda: 'K_{unsat,i}' # Unsaturated
> > hydraulic conductivity in layer i
> > sage: delyui._latex_ = lambda: '\delta_{yu,i}' # Soil layer
> > thickness in layer i
> > Traceback (most recent call last):
> > ...
> > AttributeError: 'sage.symbolic.expression.Expression' object attribute
> > '_latex_' is read-only
>
> Since Expression is a cython class, you cannot overwrite the _latex_()
> method.
>
> Pynac supports settinglatexnames forvariablesat creation, but this
> functionality is not exposed in the wrapper. Another solution by
> hacking latex_variable_name() might be possible, but I would like to
> avoid that if possible.
I was looking into Pynac/Ginac code to see how difficult it would be
to expose the Ginac's Tex_name feature for variables.
(1) Pynac allows to specify Tex_name while defining variables.
(2) Currently, pynac is patched to effectively use
latex_variable_name
for printing latex as it is better than Ginac's default print_latex
for variables
I suggest following changes:
(1) Compute latex string for variable using Sage's
"latex_variable_name"
while defining it unless user provides a latex string.
(2) Store this latex string in Ginac symbol framework and use Ginac's
print_latex method.
This would be more efficient than the current approach. For example,
if variable "alpha123" appears 10 times in an expression, currently
"latex_variable_name" function is called 10 times to typeset the
the same as "\\alpha_{123}".
On the other hand, if we store the string in Ginac then we need
to call "latex_variable_name" just once regardless of how many
times the variable appears in the expression.
BTW, I already have a hackish but working implementation
for above.
Cheers,
Golam
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