From 084448f83103092362bbfa1155a70c2fe2d3c9f8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Legat?= <benoit.legat@gmail.com>
Date: Mon, 21 Sep 2026 08:21:08 +0200
Subject: [PATCH] Implement conversion to VectorNonlinearFunction

---
 src/functions.jl                              | 12 ++++
 .../test_ScalarFunctionizeBridge.jl           | 30 ++++++++
 test/General/test_functions.jl                | 71 +++++++++++++++++++
 3 files changed, 113 insertions(+)

diff --git a/src/functions.jl b/src/functions.jl
index 23cac64f07..0dd6328135 100644
--- a/src/functions.jl
+++ b/src/functions.jl
@@ -1469,6 +1469,18 @@ function Base.convert(
     )
 end
 
+# VectorNonlinearFunction
+
+function Base.convert(
+    ::Type{VectorNonlinearFunction},
+    f::Union{VectorOfVariables,VectorAffineFunction,VectorQuadraticFunction},
+)
+    rows = ScalarNonlinearFunction[
+        convert(ScalarNonlinearFunction, row) for row in Utilities.eachscalar(f)
+    ]
+    return VectorNonlinearFunction(rows)
+end
+
 for f in (
     :ScalarAffineTerm,
     :ScalarAffineFunction,
diff --git a/test/Bridges/Constraint/test_ScalarFunctionizeBridge.jl b/test/Bridges/Constraint/test_ScalarFunctionizeBridge.jl
index 6f5e5fbf7a..eec295bef8 100644
--- a/test/Bridges/Constraint/test_ScalarFunctionizeBridge.jl
+++ b/test/Bridges/Constraint/test_ScalarFunctionizeBridge.jl
@@ -333,6 +333,36 @@ function test_FunctionConversionBridge()
     return
 end
 
+function test_FunctionConversionBridge_VectorNonlinearFunction()
+    inner = MOI.Utilities.UniversalFallback(MOI.Utilities.Model{Float64}())
+    BT = MOI.Bridges.Constraint.FunctionConversionBridge{
+        Float64,
+        MOI.VectorNonlinearFunction,
+    }
+    model = MOI.Bridges.Constraint.SingleBridgeOptimizer{BT}(inner)
+    x, y = MOI.add_variables(model, 2)
+    set = MOI.PositiveSemidefiniteConeTriangle(2)
+    for f in (
+        MOI.VectorOfVariables([x, y, x]),
+        MOI.Utilities.vectorize([1.0 * x, 2.0 * y, 3.0 * x + 1.0]),
+        MOI.Utilities.vectorize([1.0 * x * x, 2.0 * x * y, 3.0 * y * y + 1.0]),
+    )
+        @test MOI.supports_constraint(model, typeof(f), typeof(set))
+        ci = MOI.add_constraint(model, f, set)
+        bridge = MOI.get(model, MOI.Bridges.FirstBridge(), ci)
+        @test MOI.get(inner, MOI.ConstraintFunction(), bridge.constraint) ≈
+              convert(MOI.VectorNonlinearFunction, f)
+        @test MOI.get(model, MOI.ConstraintSet(), ci) == set
+        g = MOI.Utilities.eachscalar(f)[[3, 2, 1]]
+        MOI.set(model, MOI.ConstraintFunction(), ci, g)
+        @test MOI.get(inner, MOI.ConstraintFunction(), bridge.constraint) ≈
+              convert(MOI.VectorNonlinearFunction, g)
+        MOI.delete(model, ci)
+        @test !MOI.is_valid(inner, bridge.constraint)
+    end
+    return
+end
+
 function test_canonical_constraint_function()
     inner = MOI.Utilities.UniversalFallback(MOI.Utilities.Model{Float64}())
     model = MOI.Bridges.Constraint.ScalarFunctionize{Float64}(inner)
diff --git a/test/General/test_functions.jl b/test/General/test_functions.jl
index adbb29e140..2a40a0ee35 100644
--- a/test/General/test_functions.jl
+++ b/test/General/test_functions.jl
@@ -491,6 +491,77 @@ function test_convert_VectorAffineFunction_VectorQuadraticFunction()
     return
 end
 
+function test_convert_VectorNonlinearFunction_VectorOfVariables()
+    x, y = MOI.VariableIndex.(1:2)
+    for variables in ([y, x, y], MOI.VariableIndex[])
+        f = MOI.VectorOfVariables(variables)
+        g = @inferred convert(MOI.VectorNonlinearFunction, f)
+        @test MOI.output_dimension(g) == length(variables)
+        @test g ≈ MOI.VectorNonlinearFunction([
+            MOI.ScalarNonlinearFunction(:+, Any[v]) for v in variables
+        ])
+    end
+    return
+end
+
+function test_convert_VectorNonlinearFunction_VectorAffineFunction()
+    x, y = MOI.VariableIndex.(1:2)
+    for T in (Int, Float64, Rational{Int})
+        f = MOI.Utilities.vectorize([
+            T(2) * x + T(3) * y + T(4),
+            MOI.ScalarAffineFunction(MOI.ScalarAffineTerm{T}[], zero(T)),
+            MOI.ScalarAffineFunction(MOI.ScalarAffineTerm{T}[], T(5)),
+        ])
+        g = @inferred convert(MOI.VectorNonlinearFunction, f)
+        @test MOI.output_dimension(g) == 3
+        @test MOI.Utilities.eval_variables(
+            v -> T(v.value),
+            MOI.Utilities.Model{T}(),
+            g,
+        ) == T[12, 0, 5]
+        for (row, scalar) in zip(g.rows, MOI.Utilities.scalarize(f))
+            @test row ≈ convert(MOI.ScalarNonlinearFunction, scalar)
+        end
+        empty_f = MOI.VectorAffineFunction(MOI.VectorAffineTerm{T}[], T[])
+        empty_g = @inferred convert(MOI.VectorNonlinearFunction, empty_f)
+        @test isempty(empty_g.rows)
+    end
+    return
+end
+
+function test_convert_VectorNonlinearFunction_VectorQuadraticFunction()
+    x, y = MOI.VariableIndex.(1:2)
+    for T in (Int, Float64, Rational{Int})
+        f = MOI.Utilities.vectorize([
+            T(2) * x * x + T(3) * x * y + T(4) * y + T(5),
+            MOI.ScalarQuadraticFunction(
+                MOI.ScalarQuadraticTerm{T}[],
+                MOI.ScalarAffineTerm{T}[],
+                zero(T),
+            ),
+            T(2) * y * y + T(1),
+        ])
+        g = @inferred convert(MOI.VectorNonlinearFunction, f)
+        @test MOI.output_dimension(g) == 3
+        @test MOI.Utilities.eval_variables(
+            v -> T(v.value),
+            MOI.Utilities.Model{T}(),
+            g,
+        ) == T[21, 0, 9]
+        for (row, scalar) in zip(g.rows, MOI.Utilities.scalarize(f))
+            @test row ≈ convert(MOI.ScalarNonlinearFunction, scalar)
+        end
+        empty_f = MOI.VectorQuadraticFunction(
+            MOI.VectorQuadraticTerm{T}[],
+            MOI.VectorAffineTerm{T}[],
+            T[],
+        )
+        empty_g = @inferred convert(MOI.VectorNonlinearFunction, empty_f)
+        @test isempty(empty_g.rows)
+    end
+    return
+end
+
 function test_copy_ScalarNonlinearFunction()
     N = 10_000
     x = MOI.VariableIndex.(1:N)