You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: drscl.go
    path of file: ./repos/hoverfly/vendor/gonum.org/v1/gonum/lapack/gonum
    
    the code of the file until where you have to start completion: // Copyright Â©2015 The Gonum Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that 
    
func (impl Implementation) Drscl(n int, a float64, x []float64, incX int) {
	switch {
	case n < 0:
		panic(nLT0)
	case incX <= 0:
		panic(badIncX)
	}

	// Quick return if possible.
	if n == 0 {
		return
	}

	if len(x) < 1+(n-1)*incX {
		panic(shortX)
	}

	bi := blas64.Implementation()

	cden := a
	cnum := 1.0
	smlnum := dlamchS
	bignum := 1 / smlnum
	for {
		cden1 := cden * smlnum
		cnum1 := cnum / bignum
		var mul float64
		var done bool
		switch {
		case cnum != 0 && math.Abs(cden1) > math.Abs(cnum):
			mul = smlnum
			done = false
			cden = cden1
		case math.Abs(cnum1) > math.Abs(cden):
			mul = bignum
			done = false
			cnum = cnum1
		default:
			mul = cnum / cden
			done = true
		}
		bi.Dscal(n, mul, x, incX)
		if done {
			break
		}
	}
}