From d440876c009db50d1a9934be18cff112fe005c1d Mon Sep 17 00:00:00 2001
From: Vladimir Chalupecky <vladimir@chalupecky.dev>
Date: Wed, 5 May 2021 13:56:59 +0200
Subject: [PATCH] mat: panic if matrix is empty in Tridiag.Norm

---
 mat/tridiag.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mat/tridiag.go b/mat/tridiag.go
index 3537d34d..b60be342 100644
--- a/mat/tridiag.go
+++ b/mat/tridiag.go
@@ -188,6 +188,9 @@ func (a *Tridiag) Trace() float64 {
 //
 // Norm will panic with ErrNormOrder if an illegal norm is specified.
 func (a *Tridiag) Norm(norm float64) float64 {
+	if a.IsEmpty() {
+		panic(ErrZeroLength)
+	}
 	return lapack64.Langt(normLapack(norm, false), a.mat)
 }