Most performant way to subtract one array from another

Question

I have the following code which is the bottleneck in one part of my application. All I do is subtract on Array from another. Both of these arrays have more around 100000 element

Answer 1

It's not a real answer to your question, but I would investigate if I could do the subtraction already at some time while filling the arrays with values. I would optionally even consider a third array in memory to store the result of the subtraction. In modern computing, the 'cost' of memory is considerably lower than the 'cost' of the time it takes to perform an extra action on memory.

In theory you'll gain at least a little performance when the subtraction can be done while the values are still in registers or processor cache, but in practice you just might stumble upon a few tricks that could enhance performance of the entire algorithm.