backwardTape used in MATLAB2021a

I need to make some modification in built-in function when called backwardTape"

grad = backwardTape(tm,{y},{initialAdjoint},x,retainData,false,0);"

at MATLAB2021a. However, I could see the nested function when called

grad = backwardTape(tm,{y},{initialAdjoint},x,retainData,false,0)

But where is the backwardTape function? As I am running MATLAB in a cluster so I don't have authority to overwrite the built-in function called by backwardTape so I need to save some functions in my drive that I could overwrite functions.

Answer 1

[AKennedy]

In MATLAB, built-in functions like backwardTape are typically part of the proprietary codebase and are not directly accessible or modifiable by users. However, you can work around this limitation by creating a wrapper function or script that calls backwardTape and then processes its outputs according to your needs.

• Create a Wrapper Function:

function grad = myBackwardTapeWrapper(tm, y, initialAdjoint, x, retainData)
% Call the original function

grad = backwardTape(tm, {y}, {initialAdjoint}, x, retainData, false, 0);

% Modify grad as needed
% grad = yourModificationFunction(grad);
end

• Use the Wrapper: Save this function in your MATLAB path or specify its location when calling it.
• Ensure the wrapper is accessible on the cluster.

[Walter Roberson]

backwardTape is defined in deep.internal.recording.operations.DlconvBackwardOp as a method of deep.internal.recording.TapeManager . I am not sure that calling it through a wrapper is even possible.

In any case you would have to copy @dlarray and modify the copy in order to call the wrapper instead of the direct function.