help debugging my script?

Question

Christopher Maraj 2018-3-13

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/387905-help-debugging-my-script

编辑： per isakson 2018-3-18

This script is meant to solve a set of differential equations and return an output consisting of the quantities [T,X,Y,Z,U,V,W] in the form of a vector. When i run the code nothing appears, only the name of my m-file in the command window. Could someone help me find where in my code I've made a mistake?

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Christopher Maraj 2018-3-13

编辑：per isakson 2018-3-18

在 MATLAB Online 中打开

the function was called using

[T,X,Y,Z,U,V,W] = satellite(Xo,Yo,Zo,Uo,Vo,Wo,tstart,tend,maxthrust)

.

G = 6.67408*10^-11;
Me = 5.97*10^24;
Re = 6.37*10^6;
m = 1500;
dt =1;
t = 1;
total = 0;
n = 1;
while n <= n-2
      n = n +1;
      [Xthrust, Ythrust, Zthrust] = engine(tstart, tend, maxthrust, t, u, v, w)
      u(n+1) = u(n)*(Xthrust/m) -G*Me*(x(n)/((x(n).^2+y(n).^2+z(n).^2).^3/2))*dt;
      v(n+1) = v(n)*(Ythrust/m) -G*Me*(y(n)/((x(n).^2+y(n).^2+z(n).^2).^3/2))*dt;
      w(n+1) = w(n)*(Zthrust/m) -G*Me*(z(n)/((x(n).^2+y(n).^2+z(n).^2).^3/2))*dt;
      x(n+1) = x(n) + u(n+1)*dt;
      y(n+1) = y(n) + v(n+1)*dt;
      z(n+1) = z(n) + w(n+1)*dt;
      t(n+1) = t(n) + 1;
      x=x(n+1)-x(n);
      y=y(n+1)-y(n);
      z=z(n+1)-z(n);
      h = sqrt.(x^2 + y^2 + z^2) - Re;
      Vmag = sqrt(u^2 + v^2 + w^2);
      Acc = Vmag/dt;
      n = n+1;
      total = total + sqrt(x.^2 + y.^2 + z.^2);
      if total > 4.2*10^8
          break
      end
  end
  end
  % end function satellite

KSSV 2018-3-13

You need to check your while loop....the code is not executing while loop.

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Answer 1

Stephen23 2018-3-13

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https://ww2.mathworks.cn/matlabcentral/answers/387905-help-debugging-my-script#answer_309786

编辑：Stephen23 2018-3-13

在 MATLAB Online 中打开

You wrote a while condition that will never be true. Have a look at this line:

while n <= n-2

For what values of n can this be true? Can you think of any real value of n where it is less than or equal to itself minus two? Try some real number examples, if you are not sure what is going on, e.g.: