ok. an elegant way to bypass rarely changing parts of patches or subpatches:
switch inputs to ‘no data’ if there is no change and use S+H to hold last ‘real’ state of calculation:
same calculation on left and right.
left one is optimized.
if there is a change on input S+H will keep new result, but in very next frame the whole calculation will idle - because of ‘nothing to output’ from I node.