Debugging

function E = kepler (e, M)
  % E = kepler(e, M)
  % Solves kepler's equation for E, the eccentric anomoly given
  % e, the orbital eccentricity and M, the mean anomoly. 
  for i = 1:length(M)
  E(i) = fzero(@func, 1);
  end
  function out = func(E)
      out = E - e*sin(E)-M(i);
  end

end

the goal is to solve keplers equation using the zero function but I keep getting Error messages in return

[Sean de Wolski]

What error messages?

Answer 1

[Sean de Wolski]

kepler(exp(1),4)
kepler(exp(1),magic(4))

works for me...

[Kristy]

Hmmm I get this

Undefined function 'kepler' for input arguments of type

'double'.

for exactly what you put in

maybe there is another way to write my code. now I'm only getting confused

[Sean de Wolski]

Is the kepler.m file in a folder that is on your MATLAB path? I would guess not.

Either move kepler.m to your documents/MATLAB folder or add the folder it's in to your path using the pathtool. (run pathtool at the ML command line).

[Kristy]

I have it saved as kepler(1)(2) so this is what I should type in correct? I receive

Error: ()-indexing must appear last in an index expression.

[Sean de Wolski]

no....

It should be saved as 'kepler.m'

Run:

edit kepler.m

At the MATLAB command line, copy and paste the code, save it. Then try:

kepler(1,2)

at the ML command line.

[Kristy]

ok I will try this

[Jan]

Two standard suggestions:

1. Such basic questions are explained exhaustively in the Getting Started chapters of the documentation.

2. Whenever you post in this forum, that you get an error message, include the complete message also. Matlab's error messages are really helpful in 99.9% of the cases.