Merge pull request #2101 from ERGO-Code/fix-2065

Fix 2065

Author: jajhall

FEATURES.md

@@ -1,3 +1,13 @@
 ## Build changes
 
 ## Code changes
+
+Any LP offset is communicated to the IPM solver, and used in logging and primal/dual objective calculations. 
+
+If there is a valid basis when Highs::run() is called, presolve isn't skipped unless the solver option is "simplex" or "choose" (when simplex will always be chosen if there is an advanced basis).
+
+Added basis solve methods to highspy
+
+Added methods to get primal/dual ray and dual unboundedness direction to highspy
+
+

src/Highs.h

@@ -510,29 +510,31 @@ class Highs {
   }
 
   /**
-   * @brief Indicate whether a dual unbounded ray exists, and gets
-   * it if it does and dual_ray is not nullptr
+   * @brief Indicate whether a dual unbounded ray exists, and (at the
+   * expense of solving an LP) gets it if it does not and
+   * dual_ray_value is not nullptr
    */
   HighsStatus getDualRay(bool& has_dual_ray, double* dual_ray_value = nullptr);
 
   /**
-   * @brief Indicate whether a dual unbounded ray exists, and gets
-   * it if it does
+   * @brief Indicate whether a dual unbounded ray exists, and gets it
+   * if it does
    */
   HighsStatus getDualRaySparse(bool& has_dual_ray, HVector& row_ep_buffer);
 
   /**
    * @brief Indicate whether a dual unboundedness direction exists,
-   * and gets it if it does and dual_unboundedness_direction is not
-   * nullptr
+   * and (at the expense of solving an LP) gets it if
+   * dual_unboundedness_direction is not nullptr
    */
   HighsStatus getDualUnboundednessDirection(
       bool& has_dual_unboundedness_direction,
       double* dual_unboundedness_direction_value = nullptr);
 
   /**
-   * @brief Indicate whether a primal unbounded ray exists, and gets
-   * it if it does and primal_ray is not nullptr
+   * @brief Indicate whether a primal unbounded ray exists, and (at
+   * the expense of solving an LP) gets it if primal_ray is not
+   * nullptr
    */
   HighsStatus getPrimalRay(bool& has_primal_ray,
                            double* primal_ray_value = nullptr);