> 2007/7/5, fhima@xxxxxxxxxxxxxxxxx <fhima@xxxxxxxxxxxxxxxxx>:
>> > 2007/7/5, fhima@xxxxxxxxxxxxxxxxx <fhima@xxxxxxxxxxxxxxxxx>:
>> >> Hello Matrin,
>> >>
>> >> Can you say me please how i can
>> >> *derivate fe.N(i) rwt x (first composant)
>> >> *integrate on surface domaine
>> >>
>> >> Think you!
>> >
>> >
>> > diff( fe.N(i), x )
>> >
>> > ReferenceTetrahedron tet;
>> > Triangle polygon = tet.triangle(0);
>> > ex itg = polygon.integrate( fe.N(i) );
>> >
>> > There should be examples of this in the SyFi manual, and see also the
>> > ginac manual for more about diff etc.
>> >
>> > Please send further questions to syfi-dev@xxxxxxxxxx
>> >
>>
>>
>> > --
>> > ---
>> > Martin Sandve Alnæs
>> > PhD student, Cardiac Computations
>> > Simula Research Laboratory, Norway
>> >
>>
>> Matrin,
>>
>> There are a problem because fe.N(i) is not an expression of x.
>> And i have not an expression of this fuction
>
> Try this code:
> ex x1 = symbol("x");
> ex x2 = symbol("x");
> ex f = x1-x2;
> cout << f;
>
> As you can see, a symbol in ginac is not identified by its name, each
> object is a distinct symbol. You must use the global variables x, y, z
> from SyFi, not create your own. Look up get_symbol in the manual.
>
> I strongly recommend going to www.ginac.de and reading the
> documentation, at least the basics.
>
> --
> ---
> Martin Sandve Alnæs
> PhD student, Cardiac Computations
> Simula Research Laboratory, Norway
>
Matrin,
I see the manull of ginac
my problem is that i want to diffenrentiate fe.N(i) but it is impossible
because i have not the expression of fe.N(i)
If you have am idea to the expression of fe.N(i) then it is good for me
Bye
Think you
