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: dpbtrs.go
    path of file: ./repos/gonum/lapack/testlapack
    
    the code of the file until where you have to start completion: // Copyright ©2019 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 testlapack

import (
	"fmt"
	"math"
	"testing"

	"golang.org/x/exp/rand"

	"gonum.org/v1/gonum/blas"
	"gonum.org/v1/gonum/blas/blas64"
	"gonum.org/v1/gonum/floats"
)

type Dpbtrser interface {
	Dpbtrs(uplo blas.Uplo, n, kd, nrhs int, ab []float64, ldab int, b []float64, ldb int)

	Dpbtrfer
}

// DpbtrsTest tests Dpbtrs by comparing the computed and known, generated solutions of
// a linear system with a random symmetric positive definite band matrix.
func DpbtrsTest(t *testing.T, impl Dpbtrser) {
	rnd := rand.New(rand.NewSource(1))
	for _, n := range []int{0, 1, 2,
    
func dpbtrsTest(t *testing.T, impl Dpbtrser, rnd *rand.Rand, uplo blas.Uplo, n, kd, nrhs int, ldab, ldb int) {
	const tol = 1e-12

	name := fmt.Sprintf("uplo=%v,n=%v,kd=%v,nrhs=%v,ldab=%v,ldb=%v", string(uplo), n, kd, nrhs, ldab, ldb)

	// Generate a random symmetric positive definite band matrix.
	ab := randSymBand(uplo, n, kd, ldab, rnd)

	// Compute the Cholesky decomposition of A.
	abFac := make([]float64, len(ab))
	copy(abFac, ab)
	ok := impl.Dpbtrf(uplo, n, kd, abFac, ldab)
	if !ok {
		t.Fatalf("%v: bad test matrix, Dpbtrs failed", name)
	}
	abFacCopy := make([]float64, len(abFac))
	copy(abFacCopy, abFac)

	// Generate a random solution.
	xWant := make([]float64, n*ldb)
	for i := range xWant {
		xWant[i] = rnd.NormFloat64()
	}

	// Compute the corresponding right-hand side.
	bi := blas64.Implementation()
	b := make([]float64, len(xWant))
	if n > 0 {
		for j := 0; j < nrhs; j++ {
			bi.Dsbmv(uplo, n, kd, 1, ab, ldab, xWant[j:], ldb, 0, b[j:], ldb)
		}
	}

	// Solve  Uᵀ * U * X = B  or  L * Lᵀ * X = B.
	impl.Dpbtrs(uplo, n, kd, nrhs, abFac, ldab, b, ldb)
	xGot := b

	// Check that the Cholesky factorization matrix has not been modified.
	if !floats.Equal(abFac, abFacCopy) {
		t.Errorf("%v: unexpected modification of ab", name)
	}

	// Compute and check the max-norm difference between the computed and generated solutions.
	var diff float64
	for i := 0; i < n; i++ {
		for j := 0; j < nrhs; j++ {
			diff = math.Max(diff, math.Abs(xWant[i*ldb+j]-xGot[i*ldb+j]))
		}
	}
	if diff > tol {
		t.Errorf("%v: unexpected result, diff=%v", name, diff)
	}
}