If we're not counting the time to zero out the array, it seems that typed arrays are slower than plain javascript because it's converting to & from floats/doubles back and forth. Try the same with Float64Array. My microbenchmark says f32 is 15% slower than f64 on chrome: https://jsbench.me/gnkxxkjag8/1
Great catch! I assumed the JIT would identify f32 arithmetic but I guess that isn't really valid numerically. I wonder if there's a way to use Math.fround[1] on your benchmark to get expected speedups?
Yup, the spec requires computation to be as doubles and so any computation must be done that way as the end result is observable.
I didn’t know about fround but I suspect its primary use case is for trying to catch floating point overflow during double arithmetic, because again precision difference is observable.
