add Kronecker package and compat

Project.toml

@@ -16,6 +16,7 @@ FillArrays = "1a297f60-69ca-5386-bcde-b61e274b549b"
 ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
 HDF5 = "f67ccb44-e63f-5c2f-98bd-6dc0ccc4ba2f"
 IfElse = "615f187c-cbe4-4ef1-ba3b-2fcf58d6d173"
+Kronecker = "2c470bb0-bcc8-11e8-3dad-c9649493f05e"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 LinearMaps = "7a12625a-238d-50fd-b39a-03d52299707e"
 LoopVectorization = "bdcacae8-1622-11e9-2a5c-532679323890"
@@ -50,13 +51,13 @@ TrixiBase = "9a0f1c46-06d5-4909-a5a3-ce25d3fa3284"
 UUIDs = "cf7118a7-6976-5b1a-9a39-7adc72f591a4"
 
 [weakdeps]
-Makie = "ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a"
 Convex = "f65535da-76fb-5f13-bab9-19810c17039a"
 ECOS = "e2685f51-7e38-5353-a97d-a921fd2c8199"
+Makie = "ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a"
 
 [extensions]
-TrixiMakieExt = "Makie"
 TrixiConvexECOSExt = ["Convex", "ECOS"]
+TrixiMakieExt = "Makie"
 
 [compat]
 CodeTracking = "1.0.5"
@@ -73,6 +74,7 @@ FillArrays = "0.13.2, 1"
 ForwardDiff = "0.10.24"
 HDF5 = "0.16.10, 0.17"
 IfElse = "0.1"
+Kronecker = "0.5"
 LinearAlgebra = "1"
 LinearMaps = "2.7, 3.0"
 LoopVectorization = "0.12.151"
@@ -109,6 +111,6 @@ UUIDs = "1.6"
 julia = "1.8"
 
 [extras]
-Makie = "ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a"
 Convex = "f65535da-76fb-5f13-bab9-19810c17039a"
 ECOS = "e2685f51-7e38-5353-a97d-a921fd2c8199"
+Makie = "ee78f7c6-11fb-53f2-987a-cfe4a2b5a57a"

src/Trixi.jl

@@ -48,6 +48,7 @@ using FillArrays: Ones, Zeros
 using ForwardDiff: ForwardDiff
 using HDF5: HDF5, h5open, attributes, create_dataset, datatype, dataspace
 using IfElse: ifelse
+using Kronecker: Kronecker
 using LinearMaps: LinearMap
 using LoopVectorization: LoopVectorization, @turbo, indices
 using StaticArrayInterface: static_length # used by LoopVectorization