Java BigInteger alternative

Question

Is there a way to improve BigInteger performance with caching?

When you operate on BigInteger it always creates a new BigInteger. For example, when you multiply two big integers, a new BigInteger is created to host the result. I want to use some mutable version of a BigInteger that will update one of the fields with the result.

Answer 1

I doubt that the performance of your algorithm will improve if you could somehow do this, but the main principle is that BigInteger is immutable. You cannot perform an operation on it without generating a new instance, and there are good reasons to want this behavior - namely, if you have multiple threads operating on a single BigInteger, you can rest assured that these threads aren't overwriting that BigInteger directly*.

If you don't desire this behavior, your only option is to create a new class, but bear in mind that you will still be dealing with the immutability of BigIntegers at some layer.

^{*: Y'know, so long as you're not reassigning the variable...}