From 6e5297e714ec9708c9a538e78966ef94333abe08 Mon Sep 17 00:00:00 2001
From: JAJHall <jajhall@ed.ac.uk>
Date: Fri, 25 Oct 2024 13:32:41 +0100
Subject: [PATCH] Added presolve-slacks test case to TestPresolve.cpp

---
 check/TestPresolve.cpp          | 38 +++++++++++++++++++++++++++++++++
 src/qpsolver/dantzigpricing.hpp |  3 ++-
 src/qpsolver/devexpricing.hpp   |  2 ++
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/check/TestPresolve.cpp b/check/TestPresolve.cpp
index 86c5dfc469..b0a4dbc95b 100644
--- a/check/TestPresolve.cpp
+++ b/check/TestPresolve.cpp
@@ -601,3 +601,41 @@ TEST_CASE("write-presolved-model", "[highs_test_presolve]") {
   REQUIRE(highs.getInfo().simplex_iteration_count == -1);
   std::remove(presolved_model_file.c_str());
 }
+
+TEST_CASE("presolve-slacks", "[highs_test_presolve]") {
+  // This LP reduces to empty, because the equation is a doubleton
+  HighsLp lp;
+  lp.num_col_ = 2;
+  lp.num_row_ = 1;
+  lp.col_cost_ = {1, 0};
+  lp.col_lower_ = {0, 0};
+  lp.col_upper_ = {kHighsInf, kHighsInf};
+  lp.row_lower_ = {1};
+  lp.row_upper_ = {1};
+  lp.a_matrix_.start_ = {0, 1, 2};
+  lp.a_matrix_.index_ = {0, 0};
+  lp.a_matrix_.value_ = {1, 1};
+  Highs h;
+  h.setOptionValue("output_flag", dev_run);
+  REQUIRE(h.passModel(lp) == HighsStatus::kOk);
+  REQUIRE(h.presolve() == HighsStatus::kOk);
+  REQUIRE(h.getPresolvedLp().num_col_ == 0);
+  REQUIRE(h.getPresolvedLp().num_row_ == 0);
+
+  lp.num_col_ = 4;
+  lp.num_row_ = 2;
+  lp.col_cost_ = {-10, -25, 0, 0};
+  lp.col_lower_ = {0, 0, 0, 0};
+  lp.col_upper_ = {kHighsInf, kHighsInf, kHighsInf, kHighsInf};
+  lp.row_lower_ = {80, 120};
+  lp.row_upper_ = {80, 120};
+  lp.a_matrix_.start_ = {0, 2, 4, 5, 6};
+  lp.a_matrix_.index_ = {0, 1, 0, 1, 0, 1};
+  lp.a_matrix_.value_ = {1, 1, 2, 4, 1, 1};
+
+  REQUIRE(h.passModel(lp) == HighsStatus::kOk);
+  REQUIRE(h.run() == HighsStatus::kOk);
+  REQUIRE(h.presolve() == HighsStatus::kOk);
+  //  REQUIRE(h.getPresolvedLp().num_col_ == 0);
+  //  REQUIRE(h.getPresolvedLp().num_row_ == 0);
+}
diff --git a/src/qpsolver/dantzigpricing.hpp b/src/qpsolver/dantzigpricing.hpp
index 89b109e5c1..5a62dce7fb 100644
--- a/src/qpsolver/dantzigpricing.hpp
+++ b/src/qpsolver/dantzigpricing.hpp
@@ -52,8 +52,9 @@ class DantzigPricing : public Pricing {
 
  public:
   DantzigPricing(Runtime& rt, Basis& bas, ReducedCosts& rc)
+    // clang-format off
       : runtime(rt), basis(bas), redcosts(rc) {};
-
+  // clang-format on
   HighsInt price(const QpVector& x, const QpVector& gradient) {
     HighsInt minidx = chooseconstrainttodrop(redcosts.getReducedCosts());
     return minidx;
diff --git a/src/qpsolver/devexpricing.hpp b/src/qpsolver/devexpricing.hpp
index a88f3ecea5..014d8ce283 100644
--- a/src/qpsolver/devexpricing.hpp
+++ b/src/qpsolver/devexpricing.hpp
@@ -58,7 +58,9 @@ class DevexPricing : public Pricing {
       : runtime(rt),
         basis(bas),
         redcosts(rc),
+	// clang-format off
         weights(std::vector<double>(rt.instance.num_var, 1.0)) {};
+  // clang-format on
 
   // B lambda = g
   // lambda = inv(B)g