quad2.m

基于Matlab的地震数据处理显示和测井数据显示于处理的小程序

function ci = quad2(y,x)
% Function computes the numerical approximation to the definite 
% integral y dx (corresponding to sum)
% x   abscissas
% y   ordinates
% If only one input argument is given x=1:1:length(y);
% if given, x must have the same number of rows an y
% and either the same number of columns or 1 column
%    (see also cumquad)
%    ci = quad2(x,y)

[ny,my]=size(y);
dy=(y(1:ny-1,:)+y(2:ny,:))*0.5;

if (nargin == 2)
  [nx,mx]=size(x);

  if nx ~= ny
    fprintf('ERROR in QUAD1: Input arrays have incompatible dimensions\n')
    size(x), size(y)
    return
  end

  dx=diff(x);
  if mx == 1
    dx=dx(:,ones(my,1));
  elseif mx ~= my,
    fprintf('ERROR in QUAD1: Input arrays have incompatible dimensions\n')
    size(x), size(y)
    return
  end
else
  dx=ones(ny-1,my);
end
ci=sum(dx.*dy);