From 48094ded6b9c397fe41adc828d2841d9ee13cad4 Mon Sep 17 00:00:00 2001
From: "Alinson S. Xavier" <git@axavier.org>
Date: Thu, 27 Nov 2025 08:55:27 -0600
Subject: [PATCH] KnuOstWat2018: Fix eq_segprod_limit when min_uptime=1

---
 .../formulations/KnuOstWat2018/pwlcosts.jl    |   8 +++-----
 test/fixtures/issue-0057.json.gz              | Bin 0 -> 457 bytes
 test/src/UnitCommitmentT.jl                   |   2 ++
 test/src/regression.jl                        |  19 ++++++++++++++++++
 4 files changed, 24 insertions(+), 5 deletions(-)
 create mode 100644 test/fixtures/issue-0057.json.gz
 create mode 100644 test/src/regression.jl

diff --git a/src/model/formulations/KnuOstWat2018/pwlcosts.jl b/src/model/formulations/KnuOstWat2018/pwlcosts.jl
index e34db21..a70773b 100644
--- a/src/model/formulations/KnuOstWat2018/pwlcosts.jl
+++ b/src/model/formulations/KnuOstWat2018/pwlcosts.jl
@@ -67,21 +67,19 @@ function _add_production_piecewise_linear_eqs!(
                     (t < T ? Cw * switch_off[gn, t+1] : 0.0)
                 )
             else
-                # Equation (47a)/(48a) in Kneuven et al. (2020)
+                # Equation (47a) in Kneuven et al. (2020)
                 eq_segprod_limit_b[sc.name, gn, t, k] = @constraint(
                     model,
                     segprod[sc.name, gn, t, k] <=
                     g.cost_segments[k].mw[t] * is_on[gn, t] -
-                    Cv * switch_on[gn, t] -
-                    (t < T ? max(0, Cv - Cw) * switch_off[gn, t+1] : 0.0)
+                    Cv * switch_on[gn, t]
                 )
 
-                # Equation (47b)/(48b) in Kneuven et al. (2020)
+                # Equation (47b) in Kneuven et al. (2020)
                 eq_segprod_limit_c[sc.name, gn, t, k] = @constraint(
                     model,
                     segprod[sc.name, gn, t, k] <=
                     g.cost_segments[k].mw[t] * is_on[gn, t] -
-                    max(0, Cw - Cv) * switch_on[gn, t] -
                     (t < T ? Cw * switch_off[gn, t+1] : 0.0)
                 )
             end
diff --git a/test/fixtures/issue-0057.json.gz b/test/fixtures/issue-0057.json.gz
new file mode 100644
index 0000000000000000000000000000000000000000..26cb3cf15746945a641f5c16fb482cfffb21b8d6
GIT binary patch
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literal 0
HcmV?d00001

diff --git a/test/src/UnitCommitmentT.jl b/test/src/UnitCommitmentT.jl
index 473e858..1b7a011 100644
--- a/test/src/UnitCommitmentT.jl
+++ b/test/src/UnitCommitmentT.jl
@@ -23,6 +23,7 @@ include("validation/repair_test.jl")
 include("lmp/conventional_test.jl")
 include("lmp/aelmp_test.jl")
 include("market/market_test.jl")
+include("regression.jl")
 
 basedir = dirname(@__FILE__)
 
@@ -54,6 +55,7 @@ function runtests()
         lmp_aelmp_test()
         simple_market_test()
         stochastic_market_test()
+        regression_test()
     end
     return
 end
diff --git a/test/src/regression.jl b/test/src/regression.jl
new file mode 100644
index 0000000..308c36c
--- /dev/null
+++ b/test/src/regression.jl
@@ -0,0 +1,19 @@
+# UnitCommitment.jl: Optimization Package for Security-Constrained Unit Commitment
+# Copyright (C) 2020, UChicago Argonne, LLC. All rights reserved.
+# Released under the modified BSD license. See COPYING.md for more details.
+
+using UnitCommitment, HiGHS, JuMP
+
+function regression_test()
+    @testset "GitHub Issue #57" begin
+        instance = UnitCommitment.read(fixture("issue-0057.json.gz"))
+        model = UnitCommitment.build_model(
+            instance = instance,
+            optimizer = HiGHS.Optimizer,
+        )
+        JuMP.set_silent(model)
+        UnitCommitment.optimize!(model)
+        solution = UnitCommitment.solution(model)
+        @test solution["Thermal production (MW)"]["gen_524d4c85"][1] == 90.0
+    end
+end