How to trace the effect of a change in one function in a program on another function in the same program?

The general structure of my program is a fairly simple one:

main program

    function1(x,y,z);
    function2(x1,y1,z1);
    functionN(xN,yN,zN);

main program ends

Now if I change something in function1 code, how can I trace the effect of that change in the other functions that get affected.

Thanks.

[Jan]

The question is not clear enough. What does "trace the effect" mean? How are the functions affected?

[Walter Roberson]

For example, are you using global variables? Sharing data through some mechanism? Or is the structure actually different than that shown, with some of the routines having outputs that become inputs to other routines?

[Peeyush]

I think I should have been more clear in stating my question. I will try to explain again.

I have a program that calls 10 different functions. Now these 10 functions share some of the input arguments i.e. Some input variables are global and are called by two or more different functions.

Now I find I have made a mistake in the forumla in the code of one function (say function FX). So I open and change the formula in the code for that function (function FX). The output I am getting from this function is now being used by another function(s) in the main program. Is there a way to find which other variables/functions (which are dependent on the output of function FX) get affected when I make a change in function FX?

Answer 1

[Walter Roberson]

No, computing theory indicates that given the Matlab instruction set, it is not possible to analyze with certainty which variables are or are not affected by a change to another variable.

In practice, substituting something like {} in place of a numeric value will likely catch the next place the value is referenced. By inserting such assignments at strategic places one can systematically trace blocks of code affected by a variable.

Usually, though, it is much easier to use the editor's string search to look for instances of the variable name; if necessary, split the editor pane so you can compare argument lists of a function call to that of the called function so that you know the name given to the variable in the new routine.