How can I detect inside a function which output args are being used by the caller ie. those that aren't "~"?

I have a function which is called multiple times with different inputs. I don't always require all the outputs and it takes effort to provide each output, so it'd be nice to skip some of the processing for those not being used. I know about nargout, but that's only efficient if your outputs are hierarchical

eg. I want to expend the minimum amount of effort to calc a,b and c in all of these examples [a,b,c] = func(); [~,~,c] = func(); [a,~,c] = func(); [~,b] = func();

Answer 1

[Niklas Nylén]

Unless this has been added very recently there is unfortunately no way to know which outputs will actually be used. One way to achieve the same result would be to add flags to the input data and use those to select which calculations to perform.