[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 V. Kisil     email: kisilv at maths.leeds.ac.uk
--                      www: http://www.maths.leeds.ac.uk/~kisilv/

More information about the GiNaC-list mailing list