function [xx]=integr(x,dt)

% The function INTEGR performs a point wise integration
% of 2-D data x(m,n).
% Only 1st column of 2-D input data x(:,1) is processed.
%
% Calling sequence-
% [xx]=integr(x,dt)
%
% Input-
%	x	- 2-D data x(m,n)
%	dt	- the true delta t
% Output-
%	xx	- 2-D output data xx(m,1) of integrated values
%
% Used by-
% 	ACC2DIS 
 
% J.Marshak (NASA GSFC)			March 10, 2004 Modified
%			(replaced 'sum=dt*x(1,1)/2 ;' by 'sum=0;').

%----- Get dimensions
[m,n]=size(x) ;

%----- Integrate 1st column
%xx(1,1)=dt*x(1,1)/2 ;
%sum=xx(1,1) ;
sum=0.; % (JM)
for jj=2:m ;
   sum=sum+(x(jj-1,1)+x(jj,1))*dt/2    ;
   xx(jj,1)=sum ;
end