[xp,yp,zp]=precart(A,x,y,z)

function [xp,yp,zp]=precart(A,x,y,z)

% function [xp,yp,zp]=precart(A,x,y,z)
%
% precession transformation with matrix A
% for ecliptical and equatorial coordinates
% algorithms by Montenbruck/Pfleger: "Astronomy with the Personal Computer"
%
% 05.05.04 M.Penzkofer

U = A(1,1)*x+A(1,2)*y+A(1,3)*z;
V = A(2,1)*x+A(2,2)*y+A(2,3)*z;
W = A(3,1)*x+A(3,2)*y+A(3,3)*z;

xp = U;
yp = V;
zp = W;