How do i make this function write to the ode

Question

Marcus Stürup 2020-4-19

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/519061-how-do-i-make-this-function-write-to-the-ode

回答： Jyotsna Talluri 2020-4-22

采纳的回答： Jyotsna Talluri

在 MATLAB Online 中打开

Hey Fellas

I have a issue with a function where i want to share the thrust and fuelin with a ode45. when i run the program it says

"Unrecognized function or variable 'thrust'.

Error in fdsafafdafda (line 33)

thrust_stage1=thrust*1000;"

isnt the function sharing the thrust via the outputargument? how do i make it work.

function tryss
menu('how much fuel and thrust do you want? ', 'Falcon 9', ' too much fuel ','Too little fuel', ' too little thrust', 'custom');
function [thrust,fuelin]=choice(menu)
if menu ==1
    %standard Falcon 9 
    thrust=7607;
    fuelin=423;
elseif menu ==2
   
    thrust=7607;
    fuelin=1000;
    
elseif menu ==3
    
    thrust= 7607;
    fuelin=40;
    
elseif menu ==4
    
    thrust=1600;
    fuelin=423;
    
elseif menu==5
    
    thrust=input('kN thrust? ');
    fuelin=input('tons of fuel? ');
    
end
end
thrust_stage1=thrust*1000;
fuel=fuelin*1000;
thrust_stage2=934000;       %standard
tid=[0.1 1500];
SB = [0,0,0];
T=(1:1500);
opt = odeset('event', @analyse);
[t,y] = ode45(@(t,y) stage1(t,y,T,thrust_stage1, thrust_stage2,fuel),tid,SB,opt);
end

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Answer 1

Jyotsna Talluri 2020-4-22

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/519061-how-do-i-make-this-function-write-to-the-ode#answer_427622

在 MATLAB Online 中打开

Here,you are not passing a valid input to the choice function.Pass the output from the menu function,the number of the chosen item to the choice function as below.

function tryss
ch = menu('how much fuel and thrust do you want? ', 'Falcon 9', ' too much fuel ','Too little fuel', ' too little thrust', 'custom');
[thrust,fuelin]=choice(ch);
thrust_stage1=thrust*1000;
fuel=fuelin*1000;
thrust_stage2=934000;       %standard
tid=[0.1 1500];
SB = [0,0,0];
T=(1:1500);
opt = odeset('event', @analyse);
[t,y] = ode45(@(t,y) stage1(t,y,T,thrust_stage1, thrust_stage2,fuel),tid,SB,opt);
end