// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
// Copyright (C) INRIA
//
// This file must be used under the terms of the CeCILL.
// This source file is licensed as described in the file COPYING, which
// you should have received as part of this distribution. The terms
// are also available at
// http://www.cecill.info/licences/Licence_CeCILL_V2-en.txt
function v = inttrap(x,y)
//inttrap Trapezoidal numerical integration.
//v = inttrap(x,y) computes the integral of y with respect to x using
//trapezoidal integration. x and y must be vectors of the same dimension
//v = inttrap(y) computes the trapezoidal integral of y assuming unit
//spacing between the data points.
[lhs,rhs]=argn(0)
if rhs<2 then
y=x;
v=sum(y(1:$-1) + y(2:$))/2;
else
if size(x,'*')<>size(y,'*') then
error(msprintf(gettext("%s: Wrong size for input arguments: Same size expected.\n"),"inttrap"));
end
x=x(:);y=y(:);
v=(x(2:$)-x(1:$-1))'*(y(1:$-1) + y(2:$))/2;
end
endfunction