func (Implementation) Dzasum(n int, x []complex128, incX int) float64 {
	if n < 0 {
		panic(nLT0)
	}
	if incX < 1 {
		if incX == 0 {
			panic(zeroIncX)
		}
		return 0
	}
	var sum float64
	if incX == 1 {
		if len(x) < n {
			panic(shortX)
		}
		for _, v := range x[:n] {
			sum += dcabs1(v)
		}
		return sum
	}
	if (n-1)*incX >= len(x) {
		panic(shortX)
	}
	for i := 0; i < n; i++ {
		v := x[i*incX]
		sum += dcabs1(v)
	}
	return sum
}
Dzasum returns the sum of the absolute values of the elements of x
\sum_i |Re(x[i])| + |Im(x[i])|
Dzasum returns 0 if incX is negative.
package gonum
import (
	"math"
	"gonum.org/v1/gonum/blas"
	"gonum.org/v1/gonum/internal/asm/c128"
)
var _ blas.Complex128Level1 = Implementation{}