Actually, I was being overzealous. This does't quite work.
On 20.04.2012 14:40, Tom Bachmann wrote:
4. Also , identity like 1-sin(x)**2 = cos(x)**2 are not applied (try
trigsimp_groebner((1+sin(x))*(1-sin(x)) . this can be handled if
we apply all identity first as mentioned in 3rd point)
Yes. Anything beyond reducing the degree is somewhat fiddly. Basically
the algorithm excludes certain terms (in this case cos(x)**2) if it can
be rewritten in terms of smaller or equal degree. One could try to do a
final optimization step where *all* terms of said degree are used, but
this is going to get slow even faster...
In any case, thank you for pointing this issue out, I'm taking note of
it.
I went ahead and implemented this global search. Pass globl=True to
activate it. Likely very slow...
5. Perhaps in place of passing groebner basis like :
sin(x)**2*tan(x) + sin(x)*cos(x) - tan(x) (i dont know how this is
generated at first place) ,we should pass only basic formulas
(here i think you mean 1+tan(x)**2=1/cos(x)**2 )
No this does not work. The formulas have to be polynomials. In fact, the
formulas we "pass" are those listed under "ideal". The groebner basis
computation is essentially some magic. It generates many more formulae
which are needed for complicated reasons.
6. And yes sometime it gives very funny expressions
Examples?
I
Thank you :-).
--
You received this message because you are subscribed to the Google Groups
"sympy" group.
To post to this group, send email to sympy@googlegroups.com.
To unsubscribe from this group, send email to
sympy+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/sympy?hl=en.
