MATLAB: Not enough input arguments

argumentsfunction

Hello there!
I am writing a simple function but I can not understand why it will not work.
The error says "Not enough input arguments", right when the compiler is compiling the function I called ecc_anomaly.
Could you help me? I know the code is banal, though I can not fix it!
Thank you in advance!
The infamous function
function E = ecc_anomaly(tow, toe, GM, sqrta, M0, ecc)
i = 0;
M = M0+(tow-toe)*sqrt(GM/sqrta^6);
a = M0;
   while i >= 10^-13
       E = M0+ecc*sin(a); 
       i = abs(E-a);
       a = E;
   end
end
And finally my main
clc
clear all
format long
GM = 3.986005e14; % m^3/s^2
rotation = 7.2921151467e-5; % rad/s
tow = 223221; % s (self-check value)
%tow = 225445; % s
M0 = 1.94850072201; % rad
sqrta = 0.544062105942e+04; % m^0.5
ecc = 0.404827296734e-04; % unitless
toe = 0.225600000000e+06; % s
E = ecc_anomaly(tow, toe, GM, sqrta, M0, ecc);
f = t_a(ecc, E);
r = sqrta^2*(1-ecc*cos(E));
x_1 = r*cos(f);
x_2 = r*sin(f);

Best Answer

Your function is declared to accept six input arguments:
function E = ecc_anomaly(tow, toe, GM, sqrta, M0, ecc)
When you call it, you need to pass six inputs into it. When you try to call it with zero inputs like:
>> ecc_anomaly
MATLAB doesn't know what value to use as M0 on that line of code. It also doesn't know what values to use for tow, toe, GM, and sqrta, but M0 is the first variable it "sees" on that line.
There are ways to specify default values for when you call the function with fewer inputs than it's declared to accept (using functions like nargin) but easier is to call it with six inputs as you do in the "main" in the original message. I couldn't run your full "main" code since I don't have the t_a function, but I was able to run up through the ecc_anomaly call it contains.
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