distpoint.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 s=distpoint(x,y,xnot,ynot)

% s=distpoint(x,y,xnot,ynot)
%
% This function computes the distance between each pair of points represented
% by the vectors x and y and the single point xnot,ynot. That is S(j) is the 
% distance from x(j),y(j) to xnot,ynot.
% See also distcum distinc and distreach
%
% x = vector containing the x coordinates of the data points
%
% y = vector containing the y coordinates of the data points
%
% xnot = scalar x coordinate of the single point
%
% ynot = scalar y coordinate of the single point
%
% s = distance vector containing the distance between each point in
%     x and y and the point xnot,ynot
%
% by G.F. Margrave, March 1993
%
% 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.
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%
% END TERMS OF USE LICENSE

[nx,mx]=size(x);
[ny,my]=size(y);

if (nx~=ny) | (mx~=my)
	error(' Vectors must be same length');
end

s=zeros(nx);
s(1:nx,1:mx) = (x(1:nx,1:mx)-xnot).^2  +  (y(1:nx,1:mx)-ynot).^2;
s=s.^.5;