functional derivatives

*To*: mathgroup at christensen.cybernetics.net*Subject*: [mg419] functional derivatives*From*: P.Jemmer at sussex.ac.uk (Patrick Jemmer)*Date*: Mon, 23 Jan 95 17:28 GMT

Hello all: I am using density functional theory for computing propertiesd of atoms and molecules. As part of this project I am deriving the background theory. So, I need to get functional derivatives of functionals of the form: F( rho, modulus(gradient(rho)), laplacian(rho) ) I know the standard calculus of variations formula is: delta f/ delta rho = partial df/d rho - del.( partial df/ d del(rho) ) + laplacian (partial df/ d laplacian(rho) ) I have tried using ther Mathematica opperation VariationalD, but I think the problem with this is that it is designed for functionals of 1-D functions only. and so works on: delts f/ delta rho = partial df/d rho - (d/d rho')(partial df/ d rho') + (d/d rho'')(partial df/ d rho'') I was wondering how to make my own version of VariationalD to do this sort of thing. Any ideas much appreciated! Thanks. Patrick. ------------- Patrick Jemmer, Theoretical Chemistry, University of Sussex, Falmer, Brighton.