Update docs examples to use Diagonal

Author: Ickaser

docs/src/massmatrixdae/BDF.md

@@ -7,6 +7,7 @@ CollapsedDocStrings = true
 Multistep BDF methods, good for large stiff systems.
 
 ```julia
+using LinearAlgebra: Diagonal
 function rober(du, u, p, t)
     y₁, y₂, y₃ = u
     k₁, k₂, k₃ = p
@@ -15,9 +16,7 @@ function rober(du, u, p, t)
     du[3] = y₁ + y₂ + y₃ - 1
     nothing
 end
-M = [1.0 0 0
-     0 1.0 0
-     0 0 0]
+M = Diagonal([1.0, 1.0, 0])
 f = ODEFunction(rober, mass_matrix = M)
 prob_mm = ODEProblem(f, [1.0, 0.0, 0.0], (0.0, 1e5), (0.04, 3e7, 1e4))
 sol = solve(prob_mm, FBDF(), reltol = 1e-8, abstol = 1e-8)

docs/src/massmatrixdae/Rosenbrock.md

@@ -20,6 +20,7 @@ For larger systems look at multistep methods.
 ## Example usage
 
 ```julia
+using LinearAlgebra: Diagonal
 function rober(du, u, p, t)
     y₁, y₂, y₃ = u
     k₁, k₂, k₃ = p
@@ -28,9 +29,7 @@ function rober(du, u, p, t)
     du[3] = y₁ + y₂ + y₃ - 1
     nothing
 end
-M = [1.0 0 0
-     0 1.0 0
-     0 0 0]
+M = Diagonal([1.0, 1.0, 0])
 f = ODEFunction(rober, mass_matrix = M)
 prob_mm = ODEProblem(f, [1.0, 0.0, 0.0], (0.0, 1e5), (0.04, 3e7, 1e4))
 sol = solve(prob_mm, Rodas5(), reltol = 1e-8, abstol = 1e-8)