How to find out the output variable "ans" of exactly which statement is?

Hello, I have one very simple question and I will appreciate your comment!

 I have primary function and couple sub function, and when I run them I obtain the solution and one more answer "ans=..", which I don't need....
If I run in stand alone mode every one of the function I don't obatian "ans=...", only the output argument that are specified. And I can't find out where in the code is the statement that gives this "ans=...".

 Any advice is highly appreciate!
Thank you and regards!

Answer 1

[Jan]

You can step through the code using the debugger. Then run through the program until the additionoutput appears in the command window.

Another idea is FEX: Find lines without semicolon.

[EDITED] Code example to suppress the automatic assignment of ans:

function reply = myFunc(data)
value = sin(data);
if nargout ~= 0
  reply = value;
end

Now

myFunc(0.5)

displays the result of sin(0.5), but does not assign ans.

b = myFunc(0.5)

This assigns the result to b and display it.

c = myFunc(0.5);

Assignment, but no display.

[D.Chehov]

Dear Jan Simon,

It looks like that the output variable "ans=..." that I want to suppres is not appear because some of the statement in the cod is not suppres with ";". Could the reason be some other?

[Jan]

Please post how you call the program. E.g.:

sin(0.5)

creates the "ans = " output also. Then try:

a = sin(0.5);

If a function replies a value, which is not assigned to a variable, it is assigned to "ans" automatically. This can be avoid e.g. by - see [EDITED].

[D.Chehov]

I call the subfunction in this manner:

A=subfunction(inp1,inp2,...,inpN);

But I still can't find which statement replies with this unwanted output"ans=..."I tried to suppress it whit the code [EDITED], but it fails....

Do you think that it will help if I send you MyFunc....to you?

[Jan]

At first use the debugger or insert some DISP commands to find the line, which causes the output. Then post it here.

[Walter Roberson]

Jan, myFunc(0.5) is not going to display the result of sin(0.5) with that code :)

[Image Analyst]

Apparently not, but why not? I thought if you didn't accept the result of an expression into a variable and left off the semicolon, it just threw the return value of the expression into ans, which would then get echoed to the command line since the semicolon was left off. So why does

sin(1.234)

myFunc(0.5)

spit out a value for sin(1.234) but not for myFunc(0.5)?

[Jan]

I've edited the program again. The reply of a function is caught in ans as a fallback. But myFunc does not create a reply if nargout is 0. Then the the variable "reply" is not initialized and not caught in consequence.

[D.Chehov]

Well,I've found out that the unwanted output "ans=" is the same as the outcome of the line:

A=blktridiag(Amd,Asub,Asup,n);

e.g. disp (A);

I'd like to clear up, that the function "blktridiag" was taken from this forum,wherefore again thanks to its author. I modified it a litle for my case and tried in stand alone mode,where the outputs are named one!

Than I used it as a subfunction and the "ans=" appears....

I tried debugging and "echo" command ,they help...but in fact all I want at this step of the solution is to suppres the "ans.." output

Answer 2

[Image Analyst]

You need to assign it to a variable so that the variable name gets printed. So instead of something like

4*5

You'd have

a=4*5

Then it will show you the name "a" instead of just "ans"

Answer 3

[Image Analyst]

Debugging is the best way. You can also issue the "echo on" command so that each statement is printed to the window and you can scan that (it will be looooooong if you have a lot of lines of code) and try to find "ans" buried in there.