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

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Logan DiCerb on 11 Jul 2022
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!!

Bharat Chandra Mukkavalli on 12 Jul 2022
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
Hope this helps!
Rik on 12 Jul 2022
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 on 12 Jul 2022
I have corrected it

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