Not enough input arguments

i want to calculate rpm when two values approximately the same TT and T

this is the code

function rpm =zzzzzz(modelspeed,modelresistance,propellerdiameter,density,wakefraction,thrustdeduction)
va=modelspeed*(1-wakefraction);
for rpm=100:2000;

    T=modelresistance/(1-thrustdeduction);

    j=va/((rpm./60)*propellerdiameter);

    kt=0.37159*(1-(j/0.955))^0.8;

    TT=kt*density*(rpm./60)^2*propellerdiameter^4;    
    kq=0.0476*(1-(j/1.0064))^0.7;
    q=kq*density*(rpm./60)^2*propellerdiameter^5;

           if TT(rpm)/T>0.999              %when T~T’%

        rpm   

        return
    end
end

when i run this code i receive an error message ' Not enough input arguments.' for the line of this equation

va=modelspeed*(1-wakefraction);

Best Regards, Ameen

[Angus]

what are modelspeed and wakefraction?

[Angus]

really not sure if it could be causing any problems but I would encourage you to not use the name of your function as a variable inside the function. Rather

function rpm_calc = zzzzzz(...)
...
for rpm = 100:200;
...
if TT(rpm)/T>0.999
rpm_calc = rpm;
return
...

Not sure if using rpm inside the function is somehow trying to call the function again?

Answer 1

[Azzi Abdelmalek]

zzzzzz is not a script it's a function, and should be called like below

out=zzzzzz(modelspeed,modelresistance,propellerdiameter,density,wakefraction,thrustdeduction)

[ameen]

when i used out=zzzzzz(modelspeed,modelresistance,propellerdiameter,density,wakefraction,thrustdeduction)

it give me error the line you gave me

Error in z (line 1) out = zzzzzz(modelspeed,modelresistance,propellerdiameter,density,wakefraction,thrustdeduction)

[Azzi Abdelmalek]

before calling zzzzz you should assign values to modelspeed,modelresistance,...

[ameen]

i gave every variable its value in Matlab before runing the code

[Azzi Abdelmalek]

Is the error message the same?

[ameen]

yes

Answer 2

[Matt Tearle]

The error message you're getting seems to indicate a problem with how you're calling the function, rather than the function itself. I copied the function exactly as you have it, then did this:

>> zzzzzz(1,2,3,4,5,6)

And I got a different error message, related to line 10 ( if TT(rpm)/T>0.999 ).

Call the function just as I did. If you get the same error message as before, you might need to do

which zzzzzz

to figure out which function/variable MATLAB is actually finding (because it must be a different one).

Now, there are other issues with the function -- pay attention to the Code Analyzer messages you get in the Editor. I think this is what you're trying to do:

function rpm =zzzzzz(modelspeed,modelresistance,propellerdiameter,density,wakefraction,thrustdeduction)
va=modelspeed*(1-wakefraction);
for rpm=100:2000;
    T=modelresistance/(1-thrustdeduction);
    j=va/((rpm./60)*propellerdiameter);
    kt=0.37159*(1-(j/0.955))^0.8;
    TT=kt*density*(rpm./60)^2*propellerdiameter^4;
    if TT/T>0.999              %when T~T’%
        return
    end
end

There are prettier ways to do it, but that should work.