MATLAB: Variables Not Showing in Workspace After Clearing/Workspace Won’t Update Varaibles

MATLABworkspace

Hello, I am pretty new to Matlab. I have an issue. I am working on some code and want to verify my outputs as I go in the workspace. Let's say I have an array of elements that I modify in 4 different lines. I would comment out certain ones, press run, and check them in the workspace, than I would uncomment other lines working on this array to check any changes, but none are showing in the workspace even though they should. How do I get them to update in workspace after making changes to a code and pressing run?

Also, I thought clearing the workspace might help with refreshing them. I thought after I clear the workspace and run my code again, the values would appear updated. Instead, no variables are showing anymore. Can anyone help?

Best Answer

My guess is that you're working with function files rather than script files. One of the key differences between scripts and functions is that "Functions have their own workspace, separate from the base workspace. Therefore, none of the calls to the function triarea overwrite the value of a in the base workspace."

You could call your function with output arguments. If you want to see the values of the internal variables created in the function's workspace during its execution but not returned from that function as outputs you could debug the function using breakpoints.

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MATLAB: Simulink workspace

Paulo-

Thanks - that got me most of the way there. In addition to the destination workspace, I also needed a source workspace:

opts = simset('DstWorkspace','current','SrcWorkspace','current');
sim('my_model.mdl',[], opts)

MATLAB: Debugging function code and workspace variable issues

I am not sure if you can (easily) grab values from one workspace and pull them into the current function workspace... you might like to try dbup , which lets you change workspace while debugging. But variables only exist in one workspace, unless explicitly specified otherwise (e.g. global). It might be possible to do some major hackery using assignin and evalin and the like, or perhaps even calling global, but this would not be beautiful...

You are correct that when using the debugger (on a function) the workspace shown in the IDE changes from the "base" workspace to that of the (normally hidden) function itself. All of the variables that you have defined within the function are shown there, including the ones that are inputs to the function. Thus the standard way to get variables from the base workspace into a function workspace is to call that function with those variables as input arguments, as the workspaces are kept quite separate.

This page covers all of this in much more detail:

http://www.mathworks.com/help/matlab/matlab_prog/debugging-process-and-features.html

Note that scripts do not have their own workspace, as they operate in the base workspace.

Anyway, my answer for what it is worth: the simplest solution would be to change the function by adding a new argument, and then run it again.

Best Answer

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