i can't run this program , the output is (Saturation: LinearInterval: [NaN NaN]), i don't know the meaning of the ouput

%water saturation calculation
Q=input('porosity of formation=');
Rw=input('water resistivity=');
Rt=input('true resistivity=');
x=input('type of formation=');
if x==sandformation    
    f=.62/Q^2.15;
elseif x==compactedformation    
    f=1/Q^2;
elseif x==chalkyformation
    f=1/Q^2.2;
end
Ro=f*Rw;
s=sqrt(Ro/Rw);
sw=s*100;
disp(sw);

[mazen ali]

Yes, I think you should rename your m-file ... don't use the name saturation. Mazen

Answer 1

[Andrei Bobrov]

x=input('type of formation=','s');
switch  x
    case 'sandformation'    
        f=.62/Q^2.15;
    case 'compactedformation'    
        f=1/Q^2;
    otherwise % or case 'chalkyformation'
        f=1/Q^2.2;
end

[mohamed]

thank you it works correctly now, but i want to know the function of 's' inside the input function

[Andrei Bobrov]

Please, read about function input from MATLAB Documentation Center