Swapped the kIisStrategyColPriority and kIisStrategyIrreducible bits

Author: jajhall

check/TestCAPI.c

@@ -2193,7 +2193,7 @@ void testIis() {
       assert(iis_num_col == 0);
       assert(iis_num_row == 0);
       Highs_setIntOptionValue(highs, "iis_strategy",
-			      kHighsIisStrategyFromLpRowPriorityIrreducible);
+			      kHighsIisStrategyFromLpRowPriority);
     } else {
       assert(iis_num_col == 3);
       assert(iis_num_row == 2);

highs/interfaces/highs_c_api.h

@@ -145,10 +145,12 @@ static const char* const kHighsCallbackDataOutCutpoolUpperName =
     "cutpool_upper";
 
 const HighsInt kHighsIisStrategyLight = 0;
-const HighsInt kHighsIisStrategyFromLpRowPriority = 2;
-const HighsInt kHighsIisStrategyFromLpColPriority = 6;
-const HighsInt kHighsIisStrategyFromLpRowPriorityIrreducible = 10;
-const HighsInt kHighsIisStrategyFromLpColPriorityIrreducible = 14;
+// Forces full IIS calculation as before - ie with the
+// kIisStrategyIrreducible = 4 bit set, as well as the
+// kIisStrategyFromLp = 2 bit set, and possibly the
+// kIisStrategyColPriority = 8 bit set
+const HighsInt kHighsIisStrategyFromLpRowPriority = 6;
+const HighsInt kHighsIisStrategyFromLpColPriority = 14;
 
 const HighsInt kHighsIisBoundFree = 1;
 const HighsInt kHighsIisBoundLower = 2;

highs/lp_data/HConst.h

@@ -284,12 +284,12 @@ enum IisStrategy : int {
   kIisStrategyLight = kIisStrategyMin,  // 0
   kIisStrategyFromRay = 1,
   kIisStrategyFromLp = 2,
-  kIisStrategyColPriority = 4,
-  kIisStrategyIrreducible = 8,
+  kIisStrategyIrreducible = 4,
+  kIisStrategyColPriority = 8,
   kIisStrategyRelaxation = 16,
   kIisStrategyDefault = kIisStrategyLight,
   kIisStrategyMax = kIisStrategyFromRay + kIisStrategyFromLp +
-                    kIisStrategyColPriority + kIisStrategyIrreducible +
+                    kIisStrategyIrreducible + kIisStrategyColPriority +
                     kIisStrategyRelaxation
 };