Anisotropic visco-elasticity: Multiple dispatch for generalized Maxwell model

[miguelmaso]

Only added a mutiple dispatch for the generalized Maxwell model. These are the minimal changes to have a visco-elastic model with one direction of anisotropy.

In the future, it'll need more implementation: anisotropic directions are a concept orthogonal to viscous branch. Hence, we need to forward the number of directions as well the number of viscous branches to the constitutive model, in order to separate the argumens N directions and B branches.

More complicated things may appear when each direction have multiple viscous anisotropic branches...

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	main	7f32496...	main / 7f32496...
Constitutive models/Visco-elastic Ψ	0.05 ± 0.027 ms	0.0494 ± 0.028 ms	1.01 ± 0.79
Constitutive models/Visco-elastic ∂Ψu	0.0655 ± 0.0073 ms	0.0641 ± 0.0065 ms	1.02 ± 0.15
Constitutive models/Visco-elastic ∂Ψuu	0.115 ± 0.015 ms	0.114 ± 0.015 ms	1.01 ± 0.18
Simulations/StaticMechanicalDirichlet	0.142 ± 0.008 s	0.144 ± 0.0089 s	0.985 ± 0.082
Simulations/StaticMechanicalNeumann	0.136 ± 0.016 s	0.131 ± 0.013 s	1.03 ± 0.16
Simulations/ViscoElastic	20.7 s	20.9 s	0.989
Tensor algebra/Cofactor	0.07 ± 0.01 μs	0.07 ± 0.001 μs	1 ± 0.14
Tensor algebra/Det(A)Inv(A')	0.13 ± 0.001 μs	0.14 ± 0.011 μs	0.929 ± 0.073
Tensor algebra/δδ_λ_2d	30 ± 0 ns	30 ± 0 ns	1 ± 0
Tensor algebra/δδ_μ_2d	30 ± 0 ns	30 ± 0 ns	1 ± 0
time_to_load	2.44 ± 0.023 s	2.43 ± 0.013 s	1 ± 0.011

Memory benchmarks

	main	7f32496...	main / 7f32496...
Constitutive models/Visco-elastic Ψ	1.24 k allocs: 0.0777 MB	1.24 k allocs: 0.0777 MB	1
Constitutive models/Visco-elastic ∂Ψu	1.36 k allocs: 0.0898 MB	1.36 k allocs: 0.0898 MB	1
Constitutive models/Visco-elastic ∂Ψuu	2.32 k allocs: 0.155 MB	2.32 k allocs: 0.155 MB	1
Simulations/StaticMechanicalDirichlet	1.61 M allocs: 0.115 GB	1.61 M allocs: 0.115 GB	1
Simulations/StaticMechanicalNeumann	1.48 M allocs: 0.0933 GB	1.48 M allocs: 0.0933 GB	1
Simulations/ViscoElastic	0.343 G allocs: 22 GB	0.343 G allocs: 22 GB	1
Tensor algebra/Cofactor	1 allocs: 0.0781 kB	1 allocs: 0.0781 kB	1
Tensor algebra/Det(A)Inv(A')	4 allocs: 0.25 kB	4 allocs: 0.25 kB	1
Tensor algebra/δδ_λ_2d	0 allocs: 0 B	0 allocs: 0 B
Tensor algebra/δδ_μ_2d	0 allocs: 0 B	0 allocs: 0 B
time_to_load	0.149 k allocs: 11.1 kB	0.159 k allocs: 11.6 kB	0.964