Add HS201 (#345)

* ajout des modèles hs201

---------

Co-authored-by: Nathanael Leblanc <[email protected]>

src/ADNLPProblems/hs201.jl

@@ -0,0 +1,7 @@
+export hs201
+
+function hs201(; n::Int=default_nvar, type::Type{T} = Float64, kwargs...) where {T}
+    f(x) = 4 * (x[1] - 5)^2 + (x[2] - 6)^2
+    x0 = T[8, 9]
+    return ADNLPModels.ADNLPModel(f, x0, name="hs201"; kwargs...)
+end

src/Meta/hs201.jl

@@ -0,0 +1,25 @@
+hs201_meta = Dict(
+  :nvar => 2,
+  :variable_nvar => false,
+  :ncon => 0,
+  :variable_ncon => false,
+  :minimize => true,
+  :name => "hs201",
+  :has_equalities_only => false,
+  :has_inequalities_only => false,
+  :has_bounds => false,
+  :has_fixed_variables => false,
+  :objtype => :other,
+  :contype => :unconstrained,
+  :best_known_lower_bound => -Inf,
+  :best_known_upper_bound => 45.0,
+  :is_feasible => true,
+  :defined_everywhere => missing,
+  :origin => :unknown,
+)
+get_hs201_nvar(; n::Integer = default_nvar, kwargs...) = 2
+get_hs201_ncon(; n::Integer = default_nvar, kwargs...) = 0
+get_hs201_nlin(; n::Integer = default_nvar, kwargs...) = 0
+get_hs201_nnln(; n::Integer = default_nvar, kwargs...) = 0
+get_hs201_nequ(; n::Integer = default_nvar, kwargs...) = 0
+get_hs201_nineq(; n::Integer = default_nvar, kwargs...) = 0

src/PureJuMP/hs201.jl

@@ -0,0 +1,25 @@
+# Hock and Schittkowski problem number 201.
+#
+#   Source:
+#   Problem 201 in
+#   K. Schittkowski,
+#   More Test Examples for Nonlinear Programming Codes,
+#   Lectures Notes in Economics and Mathematical Systems 282,
+#   Springer Verlag, Heidelberg, 1987.
+#
+export hs201 
+"HS201 model"
+function hs201(args...; n::Int = default_nvar, kwargs...)
+    model = Model()
+
+    #Déclaration des variables
+    @variable(model, x1)
+    set_start_value(x1, 8)
+    @variable(model, x2)
+    set_start_value(x2, 9)
+
+    #Définition de la fonction objectif
+    @objective(model, Min, 4*(x1-5)^2+(x2-6)^2)
+
+    return model
+end