swiftsimd

incorrect use of `simd_all` to check a compare result on all elements?

There's probably a simple explanation for this but I can't see it. I have some code I'm trying to speed up with SIMD instructions. This is the original function:

    func near_zero() -> Bool {
        let s = 1e-8
        return (abs(e[0]) < s) && (abs(e[1]) < s) && (abs(e[2]) < s)
    }

This was my attempt:

    func near_zero() -> Bool {
        let s = 1e-8
        return simd_all(abs(v) .< s)
    }

but I'm getting an error:

No exact matches in call to global function 'simd_all'

What am I missing here?

Solution

  • (Assuming v is a SIMD3<Double>)

    The .< operator produces a SIMDMask, not a SIMD3<Double>. Use all instead of simd_all to operate on SIMDMasks.

    return all(abs(v) .< s)