updown.m

面波反演的一个例子。。。。 里面有文件说明 相信大家会好好利用的

function [lamd,lamu] = updown(thk,cvp,cvs,om,k,z,layer)

% This function calculates the up-going and down-going matrices for the P-SV case
% Note that the function psv also calculates up-going and down-going matrices
% (called du) which are optimized for use in calculating the modified R/T
% coefficients. The matrices calculated in this function are used in calculating
% the displacement-stress vectors.

% Copyright 1999 by Glenn J. Rix and Carlo G. Lai

% This program is free software; you can redistribute it and/or
% modify it under the terms of the GNU General Public License
% as published by the Free Software Foundation; either version 2
% of the License, or (at your option) any later version.
%
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
% GNU General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this program; if not, write to the Free Software
% Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

cvs2 = cvs(layer).^2; cvp2 = cvp(layer).^2;
depth = [0 ; cumsum(thk)];

lamd = zeros(2,2);
lamu = zeros(2,2);

if om == 0
   
   lamd(1,1) = exp(-k*(z-depth(layer)));
   lamd(2,2) = exp(-k*(z-depth(layer)));
   lamd(2,1) = -k*(z-depth(layer))*exp(-k*(z-depth(layer)));
   
   if layer <= length(thk)
      lamu(1,1) = exp(-k*(depth(layer+1)-z));
   	lamu(2,2) = exp(-k*(depth(layer+1)-z));
   	lamu(2,1) = -k*(depth(layer+1)-z)*exp(-k*(depth(layer+1)-z));
	end

else
   
   k2 = k^2; om2 = om^2;
   
   ks2 = om2/cvs2;
   nus = sqrt(k2-ks2);
   if imag(-i*nus) > 0;
      nus = -nus;
   end   
   
   kp2 = om2/cvp2;
   nup = sqrt(k2-kp2);
   if imag(-i*nup) > 0;
      nup = -nup;
   end   
   
   lamd(1,1) = exp(-nup*(z-depth(layer)));
   lamd(2,2) = exp(-nus*(z-depth(layer)));
   
   if layer <= length(thk)
   	lamu(1,1) = exp(-nup*(depth(layer+1)-z));
      lamu(2,2) = exp(-nus*(depth(layer+1)-z));
   end
      
end