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: level2float64.go
    path of file: ./repos/gonum/blas/gonum
    
    the code of the file until where you have to start completion: // Copyright ©2014 The Gonum Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package gonum

import (
	"gonum.org/v1/gonum/blas"
	"gonum.org/v1/gonum/internal/asm/f64"
)

var _ blas.Float64Level2 = Implementation{}

// Dger performs the rank-one operation
//
//	A += alpha * x * yᵀ
//
// where A is an m×n dense matrix, x and y are vectors, and alpha is a scalar.
func (Implementation) Dger(m, n int, alpha float64, x []float64, incX int, y []float64, incY int, a []float64, lda int) {
	if m < 0 {
		panic(mLT0)
	}
	if n < 0 {
		panic(nLT0)
	}
	if lda < max(1, n) {
		panic(badLdA)
	}
	if incX == 0 {
		panic(zeroIncX)
	}
	if incY == 0 {
		panic(zeroIncY)
	}

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

	// For zero matrix size the following slice length checks are trivially satisfied.
	if (incX > 0 && len(x) <= (m-1)*incX) || (incX < 0 && len(x) <= (1-m)*incX) {
		panic(shortX)
	}
	if (incY > 0 && len(y) <= (n-1)*incY) || (incY < 0 && len(y) <= (1-n)*incY) {
		panic(shortY)
	}
	if len(a) < lda*(m-1)+n {
		panic(shortA)
	}

	// Quick return if possible.
	if alpha == 0 {
		return
	}
	f64.Ger(uintptr(m), uintptr(n),
		alpha,
		x, uintptr(incX),
		y, uintptr(incY),
		a, uintptr(lda))
}

// Dgbmv performs one of the matrix-vector operations
//
//	y = alpha * A * x + beta * y   if
    
func (Implementation) Dsyr(ul blas.Uplo, n int, alpha float64, x []float64, incX int, a []float64, lda int) {
	if ul != blas.Lower && ul != blas.Upper {
		panic(badUplo)
	}
	if n < 0 {
		panic(nLT0)
	}
	if lda < max(1, n) {
		panic(badLdA)
	}
	if incX == 0 {
		panic(zeroIncX)
	}

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

	// For zero matrix size the following slice length checks are trivially satisfied.
	if (incX > 0 && len(x) <= (n-1)*incX) || (incX < 0 && len(x) <= (1-n)*incX) {
		panic(shortX)
	}
	if len(a) < lda*(n-1)+n {
		panic(shortA)
	}

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

	lenX := n
	var kx int
	if incX < 0 {
		kx = -(lenX - 1) * incX
	}
	if ul == blas.Upper {
		if incX == 1 {
			for i := 0; i < n; i++ {
				tmp := x[i] * alpha
				if tmp != 0 {
					atmp := a[i*lda+i : i*lda+n]
					xtmp := x[i:n]
					for j, v := range xtmp {
						atmp[j] += v * tmp
					}
				}
			}
			return
		}
		ix := kx
		for i := 0; i < n; i++ {
			tmp := x[ix] * alpha
			if tmp != 0 {
				jx := ix
				atmp := a[i*lda:]
				for j := i; j < n; j++ {
					atmp[j] += x[jx] * tmp
					jx += incX
				}
			}
			ix += incX
		}
		return
	}
	// Cases where a is lower triangular.
	if incX == 1 {
		for i := 0; i < n; i++ {
			tmp := x[i] * alpha
			if tmp != 0 {
				atmp := a[i*lda:]
				xtmp := x[:i+1]
				for j, v := range xtmp {
					atmp[j] += tmp * v
				}
			}
		}
		return
	}
	ix := kx
	for i := 0; i < n; i++ {
		tmp := x[ix] * alpha
		if tmp != 0 {
			atmp := a[i*lda:]
			jx := kx
			for j := 0; j < i+1; j++ {
				atmp[j] += tmp * x[jx]
				jx += incX
			}
		}
		ix += incX
	}
}