vint2vave.m

基于matlab的反演程序,用于地球物理勘探中射线追踪及偏移成像程序.

function vave=vint2vave(vint,t,tout)

% vave=vint2vave(vint,t,tout)
% vave=vint2vave(vint,t)
%
% VINS2VAVE computes average velocity as a function of time
% given interval velocity as a function of time.
%
% vint = input interval velocity vector
% t = input time vecot to go with vint
% tout = vector of output times at which vave estimates are
%	desired. Requirement tout >= t(1)
%*********** default tout=t *********
%
%
% G.F. Margrave June 1995, CREWES Project
%
% 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 
% project may be contacted via email at:  [e-mail]
% 
% The term 'SOFTWARE' refers to the Matlab source code, translations to
% any other computer language, or object code
%
% Terms of use of this SOFTWARE
%
% 1) Use of this SOFTWARE by any for-profit commercial organization is
%    expressly forbidden unless said organization is a CREWES Project
%    Sponsor.
%
% 2) A CREWES Project sponsor may use this SOFTWARE under the terms of the 
%    CREWES Project Sponsorship agreement.
%
% 3) A student or employee of a non-profit educational institution may 
%    use this SOFTWARE subject to the following terms and conditions:
%    - this SOFTWARE is for teaching or research purposes only.
%    - this SOFTWARE may be distributed to other students or researchers 
%      provided that these license terms are included.
%    - reselling the SOFTWARE, or including it or any portion of it, in any
%      software that will be resold is expressly forbidden.
%    - transfering the SOFTWARE in any form to a commercial firm or any 
%      other for-profit organization is expressly forbidden.
%
% END TERMS OF USE LICENSE

%test input arguments
if(length(vint)~=length(t))
	error('vint and t must have same lengths')
end

if(nargin < 3)
	%integrate vint
	dt=diff(t);
	vave=zeros(size(vint));
	nt=length(t);
	i1=2:nt;
	vave(i1)=cumsum(dt.*vint(i1-1));

	vave(i1)=vave(i1)./(t(i1)-t(1));
	vave(1)=vint(1);
else
 ind=find(tout<t(1));
 if(~isempty(ind))
		error('tout must be greater than t(1)');
	end
	vintout=pcint(t,vint,tout);
	nt=length(t);
	tnew=[t(:);tout(:)];
	vnew=[vint(:);vintout(:)];
	[tnew,it]=sort(tnew);
	vnew=vnew(it);

	nt2=length(tnew);
	dt=diff(tnew);
	vave=zeros(size(vnew));
	i1=2:nt2;
	vave(i1)=cumsum(dt.*vnew(i1-1));

	vave(i1)=vave(i1)./(tnew(i1)-tnew(1));
	ind=find(tnew==t(1));
	vave(ind)=vint(1)*ones(size(ind));

	vave(it)=vave;
	vave=vave(nt+1:length(vave));
end