%function z = trapez_test(x,y)

perm = []; nshifts = 0;

if isscalar(out.signal_x)
    z = out.signal_x * sum((out.signal_y(1:end-1,:) + out.signal_y(2:end,:)), 1)/2;
else
    z = diff(out.signal_x,1,1).' * (out.signal_y(1:end-1,:) + out.signal_y(2:end,:))/2;
end

siz = size(out.signal_y);
siz(1) = 1;
z = reshape(z,[ones(1,nshifts),siz]);
if ~isempty(perm) && ~isscalar(z)
    z = ipermute(z,perm);
end