From ca9270503f17c177bedcffe6a56174215a643c88 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Tue, 15 Aug 2023 14:37:43 +0200
Subject: [PATCH] [POC] Allow array in nonlinear expressions

---
 src/nlp_expr.jl | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/nlp_expr.jl b/src/nlp_expr.jl
index 6fe42fcb5ee..26596fb2ced 100644
--- a/src/nlp_expr.jl
+++ b/src/nlp_expr.jl
@@ -336,6 +336,10 @@ for f in MOI.Nonlinear.DEFAULT_UNIVARIATE_OPERATORS
     end
 end
 
+function LinearAlgebra.det(A::LinearAlgebra.Symmetric{<:AbstractJuMPScalar})
+    return GenericNonlinearExpr{variable_ref_type(eltype(A))}(:det, A)
+end
+
 # Multivariate operators
 
 # The multivariate operators in MOI are +, -, *, ^, /, ifelse, atan
@@ -506,6 +510,8 @@ function moi_function(f::GenericNonlinearExpr{V}) where {V}
     for i in length(f.args):-1:1
         if f.args[i] isa GenericNonlinearExpr{V}
             push!(stack, (ret, i, f.args[i]))
+        elseif arg.args[i] isa AbstractArray
+            child.args[i] = moi_function.(arg.args[i])
         else
             ret.args[i] = moi_function(f.args[i])
         end
@@ -517,6 +523,8 @@ function moi_function(f::GenericNonlinearExpr{V}) where {V}
         for j in length(arg.args):-1:1
             if arg.args[j] isa GenericNonlinearExpr{V}
                 push!(stack, (child, j, arg.args[j]))
+            elseif arg.args[j] isa AbstractArray
+                child.args[j] = moi_function.(arg.args[j])
             else
                 child.args[j] = moi_function(arg.args[j])
             end
@@ -542,6 +550,8 @@ function jump_function(model::GenericModel, f::MOI.ScalarNonlinearFunction)
             end
         elseif arg isa Number
             push!(parent.args, arg)
+        elseif arg isa AbstractArray
+            push!(parent.args, jump_function.(model, arg))
         else
             push!(parent.args, jump_function(model, arg))
         end