From b0435224119656e43f32b729231d48877de40d4f Mon Sep 17 00:00:00 2001
From: John Forrest <jjhforrest@gmail.com>
Date: Tue, 13 Aug 2024 14:37:49 +0100
Subject: [PATCH] add modifyCoefficient

---
 src/Cbc_C_Interface.cpp | 11 +++++++++++
 src/Cbc_C_Interface.h   | 12 +++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/Cbc_C_Interface.cpp b/src/Cbc_C_Interface.cpp
index cae6ae1ba..99cdd533c 100644
--- a/src/Cbc_C_Interface.cpp
+++ b/src/Cbc_C_Interface.cpp
@@ -3520,6 +3520,17 @@ Cbc_setInteger(Cbc_Model *model, int iColumn)
 
   model->solver_->setInteger(iColumn);
 }
+ 
+/** Change matrix coefficients */
+void CBC_LINKAGE
+Cbc_modifyCoefficient(Cbc_Model *model, int row, int column, double newValue )
+{
+  Cbc_flush(model);
+  VALIDATE_ROW_INDEX(row, model);
+  VALIDATE_COL_INDEX(column, model);
+
+  model->solver_->modifyCoefficient(row, column, newValue);
+}
 
 /** Adds a new column */
 void CBC_LINKAGE
diff --git a/src/Cbc_C_Interface.h b/src/Cbc_C_Interface.h
index f3c8afd11..d981d1319 100644
--- a/src/Cbc_C_Interface.h
+++ b/src/Cbc_C_Interface.h
@@ -408,7 +408,17 @@ Cbc_setContinuous(Cbc_Model *model, int iColumn);
   **/
 CBCLIB_EXPORT void CBC_LINKAGE
 Cbc_setInteger(Cbc_Model *model, int iColumn);
-
+  
+/** @brief Change matrix coefficients
+  *
+  * @param model problem object
+  * @param row row index
+  * @param column column index
+  * @param newValue new value of the coefficient
+  **/
+CBCLIB_EXPORT void CBC_LINKAGE
+Cbc_modifyCoefficient(Cbc_Model *model, int row, int column, double newValue);
+  
 /** @brief Frees memory of model object 
   *
   * @param model problem object */