drayveclin.m

利用射线追踪法实现地震波场层析成像.在石油行业中,此过程是地震资料应用的一个重要步骤

function drdt=drayveclin(t,r)
% DRAYVECLIN: compute the derivative of ray vector for v0=a*x+b*z
%
% drdt=drayveclin(t,r)
%
% This is the fundamental driver for v(x,z) raytracing.
% The velocity model is defined by first calling rayvelmod.
% t ... scalar giveg the current time
% r ... 4x1 column vector giving (x,z,p,q)
% drdt ... 4x1 column vector giving the time-derivative of r
%
%
% by G.F. Margrave, CREWES, June 2000
%
% NOTE: It is illegal for you to use this software for a purpose other
% than non-profit education or research UNLESS you are employed by a CREWES
% Project sponsor. By using this software, you are agreeing to the terms
% detailed in this software's Matlab source file.
 
% BEGIN TERMS OF USE LICENSE
%
% This SOFTWARE is maintained by the CREWES Project at the Department
% of Geology and Geophysics of the University of Calgary, Calgary,
% Alberta, Canada.  The copyright and ownership is jointly held by 
% its author (identified above) and the CREWES Project.  The CREWES 
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x=r(1);z=r(2);p=r(3);q=r(4);

drdt=zeros(size(r));


a0=1800;g=0.75;h=0;

alpha=a0+g*z+h*x;
drdt(1)=(alpha^2)*p;
drdt(2)=(alpha^2)*q;
drdt(3)=-h/alpha;
drdt(4)=-g/alpha;