diff --git a/lapack/gonum/dlanhs.go b/lapack/gonum/dlanhs.go
index 9df33e16..88c78624 100644
--- a/lapack/gonum/dlanhs.go
+++ b/lapack/gonum/dlanhs.go
@@ -15,15 +15,19 @@ import (
 // the infinity norm, or the element of largest absolute value of a
 // Hessenberg matrix A.
 //
-// On using norm=lapack.MaxRowSum, the vector work must have length n.
+// On using norm=lapack.MaxColumnSum, the vector work must have length n.
 func (impl Implementation) Dlanhs(norm lapack.MatrixNorm, n int, a []float64, lda int, work []float64) float64 {
 	switch {
 	case n < 0:
 		panic(nLT0)
 	case lda < max(1, n):
 		panic(badLdA)
-	case norm == lapack.MaxRowSum && len(work) < n:
+	case len(a) < (n-1)*lda+n:
+		panic(shortA)
+	case norm == lapack.MaxColumnSum && len(work) < n:
 		panic(badLWork)
+	case norm != lapack.MaxRowSum && norm != lapack.MaxAbs && norm != lapack.MaxColumnSum && norm != lapack.Frobenius:
+		panic(badNorm)
 	}
 	if n == 0 {
 		return 0 // Early return.
@@ -32,8 +36,6 @@ func (impl Implementation) Dlanhs(norm lapack.MatrixNorm, n int, a []float64, ld
 	bi := blas64.Implementation()
 	var value float64
 	switch norm {
-	default:
-		panic(badNorm)
 	case lapack.MaxAbs:
 		for i := 0; i < n; i++ {
 			minj := max(0, i-1)
diff --git a/lapack/testlapack/dlanhs.go b/lapack/testlapack/dlanhs.go
index ac782507..9cd92b98 100644
--- a/lapack/testlapack/dlanhs.go
+++ b/lapack/testlapack/dlanhs.go
@@ -19,13 +19,17 @@ type Dlanhser interface {
 
 func DlanhsTest(t *testing.T, impl Dlanhser) {
 	const tol = 1e-15
-	work := make([]float64, 9)
+	allwork := make([]float64, 9)
 	rnd := rand.New(rand.NewSource(1))
 	for _, n := range []int{1, 2, 4, 9} {
 		for _, lda := range []int{n, n + 5} {
 			a := randomHessenberg(n, lda, rnd)
 			for _, norm := range []lapack.MatrixNorm{lapack.MaxAbs, lapack.MaxRowSum, lapack.MaxColumnSum, lapack.Frobenius} {
-				for i := range work[:n] {
+				var work []float64
+				if norm == lapack.MaxColumnSum {
+					work = allwork[:n]
+				}
+				for i := range work {
 					work[i] = math.NaN()
 				}
 				want := dlange(norm, a.Rows, a.Cols, a.Data, a.Stride)