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

function constantwattksi = 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);

constantwattksi=1-YZA./YMA;