From 3c3917e46ee788a0cd8da6f38d9df162a988a37f Mon Sep 17 00:00:00 2001
From: Hendrik Ranocha <ranocha@users.noreply.github.com>
Date: Sat, 1 Feb 2025 11:12:11 +0100
Subject: [PATCH] use banded matrix decomposition instead of dense LU for
 BBM-BBM (#170)

---
 src/equations/bbm_bbm_1d.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/equations/bbm_bbm_1d.jl b/src/equations/bbm_bbm_1d.jl
index 99cfd788..20d93724 100644
--- a/src/equations/bbm_bbm_1d.jl
+++ b/src/equations/bbm_bbm_1d.jl
@@ -371,7 +371,7 @@ function create_cache(mesh, equations::BBMBBMEquations1D,
     N = nnodes(mesh)
     M = mass_matrix(solver.D1)
     Pd = BandedMatrix((-1 => fill(one(real(mesh)), N - 2),), (N, N - 2))
-    D2d = (sparse(solver.D2) * Pd)[2:(end - 1), :]
+    D2d = (BandedMatrix(solver.D2) * Pd)[2:(end - 1), :]
     # homogeneous Dirichlet boundary conditions
     invImD2d = lu(I - 1 / 6 * D2d * K_i)
     m = diag(M)