[GiNaC-list] Differentiation of a function with respect to a tensor
Vladimir V. Kisil
kisilv at maths.leeds.ac.uk
Thu Feb 10 22:36:26 CET 2011
Dear Bernardo,
>>>>> On Thu, 10 Feb 2011 16:11:41 -0200, Bernardo Rocha <bernardosk at gmail.com> said:
BMR> Well, defining the function as a GiNaC expression is part of my
BMR> doubt,
You need to define an indexed object, see respective section
(4.14.1) in the manual. In the example
symbol i_sym("i"), j_sym("j");
idx i(i_sym, 3), j(j_sym, 3);
symbol A("A");
ex E=indexed(A, i, j);
you need to replace A by a suitable GiNaC expression, which will
encode properties of your tensor. In some cases you may need to define
your own class for it if you wish a fine control on its behaviour.
Best wishes,
Vladimir
--
Vladimir V. Kisil email: kisilv at maths.leeds.ac.uk
-- www: http://www.maths.leeds.ac.uk/~kisilv/
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