Function will not run or produce answers

% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
clear all;
clc  

function [r, v] = rv_from_coe(coe,mu)
% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
%{
  This function computes the state vector (r,v) from the
  classical orbital elements (coe).
 
  mu   - gravitational parameter (km^3;s^2)
  coe  - orbital elements [a e incl Om w TA]
         where
             a    - semimajor axis (km)
             e    = eccentricity
             incl = inclination of the orbit (rad)
             Om   = longitude of the ascending node (rad)
             w    = argument of perigee (rad)
             TA   = true anomaly (rad)
  p    - semi-latus rectum (km)
  h    - the magnitude of H (km^2/s)
  R3_w - Rotation matrix about the z-axis through the angle w
  R1_i - Rotation matrix about the x-axis through the angle i
  R3_W - Rotation matrix about the z-axis through the angle Om
  Q_pX - Matrix of the transformation from perifocal to geocentric 
         equatorial frame
  rp   - position vector in the perifocal frame (km)
  vp   - velocity vector in the perifocal frame (km/s)
  r    - position vector in the geocentric equatorial frame (km)
  v    - velocity vector in the geocentric equatorial frame (km/s)

  User M-functions required: none
%}
% ----------------------------------------------
mu= 398600; %km3/s2 

coe=[10632 0.3184 0.523409 1.74101 0.981203 2.56632]
a    = coe(1);
e    = coe(2);
incl = coe(3);
Om   = coe(4);
w    = coe(5);
TA   = coe(6);

p = a*(1-e^2) ;
h = sqrt(mu*p) ;

%...Equations 4.45 and 4.46 (rp and vp are column vectors):
rp = (h^2/mu) * (1/(1 + e*cos(TA))) * (cos(TA)*[1;0;0] + sin(TA)*[0;1;0]);
vp = (mu/h) * (-sin(TA)*[1;0;0] + (e + cos(TA))*[0;1;0]);

%...Equation 4.34:
R3_W = [ cos(Om)  sin(Om)  0
        -sin(Om)  cos(Om)  0
            0        0     1];

%...Equation 4.32:
R1_i = [1       0          0
        0   cos(incl)  sin(incl)
        0  -sin(incl)  cos(incl)];

%...Equation 4.34:
R3_w = [ cos(w)  sin(w)  0 
        -sin(w)  cos(w)  0
           0       0     1];

%...Equation 4.49:
Q_pX = (R3_w*R1_i*R3_W)';

%...Equations 4.51 (r and v are column vectors):
r = Q_pX*rp;
v = Q_pX*vp;

%...Convert r and v into row vectors:
r = r';
v = v';

end
% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Every time I run my script I get this error, if I change the file name then I get no results in my workspace or command window? Please help, I'm not sure whats wrong.

Error: File: rv_from_coe.m Line: 5 Column: 19

Local function name must be different from the script name.

Answer 1

[madhan ravi]

Remove first 2 lines.

Your function doesn’t need any input arguments.

You must call a function not simply clicking the green triangular button.

 doc function % a must read

[Areg Arzoomanian]

% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
function [r, v] = rv_from_coe(coe,mu)
% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
%{
  This function computes the state vector (r,v) from the
  classical orbital elements (coe).
 
  mu   - gravitational parameter (km^3;s^2)
  coe  - orbital elements [a e incl Om w TA]
         where
             a    - semimajor axis (km)
             e    = eccentricity
             incl = inclination of the orbit (rad)
             Om   = longitude of the ascending node (rad)
             w    = argument of perigee (rad)
             TA   = true anomaly (rad)
  p    - semi-latus rectum (km)
  h    - the magnitude of H (km^2/s)
  R3_w - Rotation matrix about the z-axis through the angle w
  R1_i - Rotation matrix about the x-axis through the angle i
  R3_W - Rotation matrix about the z-axis through the angle Om
  Q_pX - Matrix of the transformation from perifocal to geocentric 
         equatorial frame
  rp   - position vector in the perifocal frame (km)
  vp   - velocity vector in the perifocal frame (km/s)
  r    - position vector in the geocentric equatorial frame (km)
  v    - velocity vector in the geocentric equatorial frame (km/s)

  User M-functions required: none
%}
% ----------------------------------------------
mu= 398600; %km3/s2 

coe=[10632 0.3184 0.523409 1.74101 0.981203 2.56632];
a    = coe(1);
e    = coe(2);
incl = coe(3);
Om   = coe(4);
w    = coe(5);
TA   = coe(6);

p = a*(1-e^2) ;
h = sqrt(mu*p) ;

%...Equations 4.45 and 4.46 (rp and vp are column vectors):
rp = (h^2/mu) * (1/(1 + e*cos(TA))) * (cos(TA)*[1;0;0] + sin(TA)*[0;1;0]);
vp = (mu/h) * (-sin(TA)*[1;0;0] + (e + cos(TA))*[0;1;0]);

%...Equation 4.34:
R3_W = [ cos(Om)  sin(Om)  0
        -sin(Om)  cos(Om)  0
            0        0     1];

%...Equation 4.32:
R1_i = [1       0          0
        0   cos(incl)  sin(incl)
        0  -sin(incl)  cos(incl)];

%...Equation 4.34:
R3_w = [ cos(w)  sin(w)  0 
        -sin(w)  cos(w)  0
           0       0     1];

%...Equation 4.49:
Q_pX = (R3_w*R1_i*R3_W)';

%...Equations 4.51 (r and v are column vectors):
r = Q_pX*rp;
v = Q_pX*vp;

%...Convert r and v into row vectors:
r = r';
v = v';

end
% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Thank you, but even when I do this nothing even appears in my work space

[Walter Roberson]

You have to invoke the function from the command line, in a way that assigns values to variables.

[MyR, MyV] = rv_from_coe();

The function is written to accept arguments, but there is no point in passing any arguments to the function as the function overwrites the variables involved .