constantwattksi(modelZA,modelMA,Z,P,ds)

function [ksiMAt ksiMA] = constantwattksi(modelZA,modelMA,Z,P,ds)

%constantwatt(model,Z,P) selects the values from the model in the operation points
%with the same power input P. The distance on the constant power curve is
%ds. Normally ds is taken as 1. Z is the transmission rate of the given
%model.

c=P*3.6*Z;
vmax=25;
Tmax=75;
Tmin=c/vmax;
vmin=c/Tmax;
y(1)=Tmax;
ynew(1)=y(1);
%x=vmin:0.1:vmax;

x(1)=vmin;
k=1;
while x(k)<vmax
    dx(k)=ds/(sqrt(1+c^2/x(k)^4));
    x(k+1)=x(k)+dx(k);
    k=k+1;
end

xnew=x; 
ynew=c./xnew;
 
 
Xnew=[xnew',ynew'];
YZA=simlssvm(modelZA,Xnew);
YMA=simlssvm(modelMA,Xnew);
PtZA=YZA.*(xnew'/3.6);
PtMA=YMA.*(xnew'/3.6);

WtZA=mean(PtZA)
WtMA=mean(PtMA);
WtmMA=WtMA-WtZA;
ksiMA=WtmMA/WtMA;

%not necessary, input is always 50!!
% n=1;
% for k=1:length(PtZA)
%     if PtZA(k)>2
%         PtmMA(n)=PtMA(k)-PtZA(k);
%         PtZAf(n)=PtZA(k);
%         n=n+1;
%     end
% end
%size(PtZAf)
%size(PtZA)
PtmMA=PtMA-PtZA;
ksiMAt=PtmMA./PtMA;