I am having trouble creating a loop for inputs into a function

I have a MATLAB code and function that finds values needed for a turbojet analysis and here is the function I created and I am calling for a project:

[ST,S,Thrust] = dualspoolturbofan(M_0,mdot_0,T_0,p_0,pi_dmax,T_t4,eff_b,pi_b,h_PR,alpha,pi_cL,pi_c,pi_f,gamma_c,cp_c,e_cL,e_cH,gamma_t,cp_t,e_tL,e_tH,e_f,eff_mH,eff_mL,pi_n,pi_fn,p0_p9,gc);

My problem statement is to then plot the outputs vs M_0 (3v1 graph), while M_0 changes from (0.0,0.9,30) (30 values between 0.0 & 0.9), and T_t4 changes from 2800,3200,3400 (just those 3 values)

So 90 total changed inputs with the 30 Mach values and 3 temperature values. I am just stuck on what loops to create to satisfy this problem statement. Thanks so much!!

Answer 1

[Bharat Chandra Mukkavalli]

Hi,

As I understand, you want to plot three graphs ST vs M_0, S vs M_0 and Thrust vs M_0 for different discrete values of T_t4.

You can run the following loops to achieve this:

M_0 = linspace(0, 0.9, 30);

titledlayout(3, 1);

for temp in [2800, 3200, 3400]

ST_vec = [];

S_vec = [];

Thrust_vec = [];

for m in M_0

[ST,S,Thrust] = dualspoolturbofan(m, ..., temp, ...);

ST_vec(end+1) = ST;

S_vec(end+1) = S;

Thrust_vec(end+1) = Thrust;

end

nexttile

hold on

plot(M_0, ST_vec);

plot(M_0, S_vec);

plot(M_0, Thrust_vec);

hold off

end

Refer to the link here on plotting multiple plots: https://in.mathworks.com/help/matlab/creating_plots/combine-multiple-plots.html

Hope this helps!

[Rik]

for temp in [2800, 3200, 3400]

Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other syntax error. To construct matrices, use brackets instead of parentheses.

Error in connector.internal.fevalMatlab

Error in connector.internal.fevalJSON

end

As you can see, this syntax results in a syntax error.

[Bharat Chandra Mukkavalli]

The below code should work:

M_0 = linspace(0, 0.9, 30);

titledlayout(3, 1);

for temp = [2800 3200 3400]

ST_vec = [];

S_vec = [];

Thrust_vec = [];

for m = M_0

[ST,S,Thrust] = dualspoolturbofan(m, ..., temp, ...);

ST_vec(end+1) = ST;

S_vec(end+1) = S;

Thrust_vec(end+1) = Thrust;

end

nexttile

hold on

plot(M_0, ST_vec);

plot(M_0, S_vec);

plot(M_0, Thrust_vec);

hold off

end

Thank you Rik for pointing it out!

[Rik]

No, it does not. 'in' is not a valid Matlab syntax. You can easily check this by formatting your code as a code section, instead of an inserted example.

M_0 = linspace(0, 0.9, 30);
titledlayout(3, 1);
for temp in [2800 3200 3400]

Invalid expression. Check for missing multiplication operator, missing or unbalanced delimiters, or other syntax error. To construct matrices, use brackets instead of parentheses.

Error in connector.internal.fevalMatlab

Error in connector.internal.fevalJSON

    ST_vec = [];
    S_vec = [];
    Thrust_vec = [];    
    for m in M_0
        [ST,S,Thrust] =  dualspoolturbofan(m, ..., temp, ...);
        ST_vec(end+1) = ST;
        S_vec(end+1) = S;
        Thrust_vec(end+1) = Thrust;
    end
    nexttile
    hold on
    plot(M_0, ST_vec);
    plot(M_0, S_vec);
    plot(M_0, Thrust_vec);
    hold off
end     

[Bharat Chandra Mukkavalli]

I have corrected it