Better Performance with large math calculations?

Solar2D General Questions/Discussion
#1

Hi everyone,

My game is pretty simple graphics wise (not much happening on-screen), but I need to do some pretty big calculations. I’m currently running the game at 60fps but only doing the math every 30fps to help lower CPU usage.

Example: Having a number of 950 quintillion and adding 4 quadrillion to it. I do this multiple times per frame like I mentioned, and the CPU usage is basically always maxed out doing tons of calculations like this. What’s the best way to improve this? I’m generally only doing addition, but I also do a couple divisions and multiplications each time as well (30 fps).

Thanks!

#2

I can’t specifically answer but the #1 performance boost step for these things is to localize the function

local mRandom = math.random() mRandom(34)

That’s mainly for doing lots of calls though, not a single “big” call. Not really sure how math functions handle big numbers though unless I’m wrong up to 9 quntillion is still a 64-bit integer…

#3

Thanks for the super quick reply. Yeah, I already localize all math functions like that. You’re right about it handling up to 9 quintillion as a 64bit int. My numbers go above that pretty easily though. Currently looking around to find general lua math optimization tricks as well. 

#4

If adding large numbers took longer than adding small numbers (it doesn’t, right? This is lua after all…), then one potential optimization question would be - how much precision do you need? You could divide the initial numbers by 10^9 or something, do your small number calcs, and multiply back…

But it takes just as long to add small variables as large - given that lua doesn’t use integers… I’d guess you’re best improvements will come in (literally) re-factoring your math (moving some things out of the main calculations) / changing your algorithm (breaking the 30 fps calculations into one 1 fps calc doing more heavy lifting, and a lighter 30 fps calc, or some other such reorganization).

#5

I can’t specifically answer but the #1 performance boost step for these things is to localize the function

local mRandom = math.random() mRandom(34)

That’s mainly for doing lots of calls though, not a single “big” call. Not really sure how math functions handle big numbers though unless I’m wrong up to 9 quntillion is still a 64-bit integer…

#6

Thanks for the super quick reply. Yeah, I already localize all math functions like that. You’re right about it handling up to 9 quintillion as a 64bit int. My numbers go above that pretty easily though. Currently looking around to find general lua math optimization tricks as well. 

#7

If adding large numbers took longer than adding small numbers (it doesn’t, right? This is lua after all…), then one potential optimization question would be - how much precision do you need? You could divide the initial numbers by 10^9 or something, do your small number calcs, and multiply back…

But it takes just as long to add small variables as large - given that lua doesn’t use integers… I’d guess you’re best improvements will come in (literally) re-factoring your math (moving some things out of the main calculations) / changing your algorithm (breaking the 30 fps calculations into one 1 fps calc doing more heavy lifting, and a lighter 30 fps calc, or some other such reorganization).