How to pass variables from one file to another?

Hello all, I have two function file in matlab (not in simulink even though the picture is in simulink. Plus, the solvers I am using to solve my optimal control problem are not compatible with simulink). I have function file for block 1 fn U=guidance(X). And 2 files for 2nd block, i.e fn X=state_propagation(U) and run file of this function. I am having troubling closing the loop, i.e. the output U(vector) from first block (function) is a input to the second function and output X from second function is the input to the first function. How can I close both these variable passing loops from one file to another. Can someone please help?

[Stephen23]

https://www.mathworks.com/help/matlab/matlab_prog/share-data-between-workspaces.html

https://www.mathworks.com/help/matlab/creating_guis/share-data-among-callbacks.html

Do NOT use global variables, assignin, or evalin.

[DB]

Thanks. This is helpful. What is the reason for NOT using global variables, assignin or evalin?

[Stephen23]

@Divya Bhatia: using global variables makes code liable to bugs that are very hard to debug. Using evalin and assignin makes code slow, buggy, and hard to debug.

https://www.mathworks.com/help/matlab/matlab_prog/share-data-between-workspaces.html

http://matlab.wikia.com/wiki/FAQ#Are_global_variables_bad.3F

https://www.mathworks.com/matlabcentral/answers/351423-problem-with-global-variables

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

and hundreds of other threads where these topics have been discussed.

Answer 1

[Walter Roberson]

http://matlab.wikia.com/wiki/FAQ#How_can_I_share_data_between_callback_functions_in_my_GUI.28s.29.3F