Vector APIを使った

vector.scala.sc

//> using scala 3.4.0
//> using dep "com.outr::scribe::3.13.2"

// run via:
// scala-cli -J --add-modules -J jdk.incubator.vector -J -Xmx16G  vector.scala.sc

import jdk.incubator.vector.*
import scribe._

def mult2a(arr: Array[Double]): Array[Double] = arr.map(_ * 1.618)

inline def mult2v(
  SP: VectorSpecies[java.lang.Double],
  arr: Array[Double],
): Array[Double] = {
  val buf      = new Array[Double](arr.size)
  var idx      = 0
  val spLength = SP.length()

  while (idx < SP.loopBound(arr.size)) {
    val mask   = SP.indexInRange(idx, arr.size)
    val vec    = DoubleVector.fromArray(SP, arr, idx, mask)
    val result = vec.mul(1.618)
    result.intoArray(buf, idx, mask)
    idx = idx + spLength
  }

  // handle the remaining elements
  (idx to arr.size - 1) foreach { i =>
    buf(i) = arr(i) * 1.618
  }
  buf
}

scribe.info("building array")
val hugeArray: Array[Double] =
  (0 to 1_000_000).toArray.map(_.toDouble)
scribe.info("done")

scribe.info("mult2a")
val v1 = scribe.elapsed {
  val result = mult2a(hugeArray)
  scribe.info("done")
  result
}
scribe.info(v1.take(10).mkString(", "))

scribe.info("mult2v")
inline def SP = DoubleVector.SPECIES_PREFERRED
val v2 = scribe.elapsed {
  val result = mult2v(SP, hugeArray)
  scribe.info("done")
  result
}
scribe.info(v2.take(10).mkString(", "))

scribe.info("checking")
val asserted = assert(v1.sameElements(v2))

// ---

scribe.info("repeating mult2a")
val repeatedV1 = scribe.elapsed {
  (0 to 10000).foreach { _ =>
    mult2a(hugeArray)
  }
  scribe.info("done")
}

scribe.info("repeating mult2v")
val repeatedV2 = scribe.elapsed {
  (0 to 10000).foreach { _ =>
    mult2v(SP, hugeArray)
  }
  scribe.info("done")
}