Added EvolutionLaw struct

[miguelmaso]

The EvolutionLaw struct allows to easily construct evolution functions

# Create base laws
r = ramp(0.2)   # Returns an EvolutionLaw

# Apply arithmetic
# This creates a NEW function: t -> 2.0 * ramp(0.2)(t) + 5.0
complex_load = 2 * r + 5

[github-actions]

Benchmark Results (Julia v1)

Time benchmarks

	main	1478534...	main / 1478534...
Constitutive models/Visco-elastic Ψ	0.0509 ± 0.027 ms	0.0501 ± 0.0098 ms	1.02 ± 0.57
Constitutive models/Visco-elastic ∂Ψu	0.0677 ± 0.0038 ms	0.0657 ± 0.0065 ms	1.03 ± 0.12
Constitutive models/Visco-elastic ∂Ψuu	0.118 ± 0.017 ms	0.116 ± 0.016 ms	1.02 ± 0.2
Simulations/StaticMechanicalDirichlet	0.15 ± 0.0089 s	0.147 ± 0.0085 s	1.02 ± 0.085
Simulations/StaticMechanicalNeumann	0.13 ± 0.015 s	0.134 ± 0.014 s	0.974 ± 0.15
Simulations/ViscoElastic	8.66 s	8.45 s	1.03
Tensor algebra/Cofactor	0.069 ± 0.01 μs	0.07 ± 0.01 μs	0.986 ± 0.2
Tensor algebra/Det(A)Inv(A')	0.14 ± 0.01 μs	0.131 ± 0.01 μs	1.07 ± 0.11
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	2.8 ± 0.05 s	2.79 ± 0.027 s	1 ± 0.02

Memory benchmarks

	main	1478534...	main / 1478534...
Constitutive models/Visco-elastic Ψ	1.25 k allocs: 0.0789 MB	1.25 k allocs: 0.0789 MB	1
Constitutive models/Visco-elastic ∂Ψu	1.37 k allocs: 0.0911 MB	1.37 k allocs: 0.0911 MB	1
Constitutive models/Visco-elastic ∂Ψuu	2.33 k allocs: 0.158 MB	2.33 k allocs: 0.158 MB	1
Simulations/StaticMechanicalDirichlet	1.59 M allocs: 0.114 GB	1.59 M allocs: 0.114 GB	1
Simulations/StaticMechanicalNeumann	1.41 M allocs: 0.0901 GB	1.41 M allocs: 0.0901 GB	1
Simulations/ViscoElastic	0.128 G allocs: 8.26 GB	0.128 G allocs: 8.26 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	0.149 k allocs: 11.1 kB	1