Does Sven's ult stack with double damage?

Question

Does Sven's ult stack with double damage? If it does, does the order of activating ult and double damage make any difference?

Answer 1

Sven's ultimate gives you 100%/150%/200% bonus damage.

Only increases base damage and that given by the primary attribute of Sven. Raw bonus damage is not increased.
– Sven - Dota 2 Wiki

Your damage consists of 2 numbers: A +B, and this description basically means that the ultimate gives you 100%/150%/200% of the A number. It excludes raw damage items (but items that give Strength still count)

Exactly the same can be said about the Double Damage rune: it gives you 100% of A.

Since both of these only increase B and are based only on A, their bonuses will not be multiplied with each other; they're completely independent. But they do stack in a sense. The order of activating them does not make a difference, and it probably wouldn't make a difference even if they stacked in some complicated way.

So if you have both Double Damage and Sven's ultimate level 3 active, your total damage will be:
A+B + A*2 + A (the 2 stands for 200%).