Merge pull request opencobra#1017 from lvalcarcelg/problem_infeasible…

…_cplex_solveMILP

🐛 Fixing bug for MILP solver using IBM CPLEX

src/base/solvers/solveCobraMILP.m

@@ -357,7 +357,11 @@
         else
            solStat = -1; % Solution not optimal or solver problem
         end
+
     case 'ibm_cplex'
+        % Free academic licenses for the IBM CPLEX solver can be obtained from
+        % https://www.ibm.com/developerworks/community/blogs/jfp/entry/CPLEX_Is_Free_For_Students?lang=en
+
         cplexlp = Cplex();
         if (~isempty(csense))
             b_L(csense == 'E') = b(csense == 'E');
@@ -432,11 +436,12 @@
         end
 
         % Get results
-        x = Result.x;
-        f = osense*Result.objval;
         stat = Result.status;
         if (stat == 101 || stat == 102 || stat == 1)
             solStat = 1; % Opt integer within tolerance
+            % Return solution if problem is feasible, bounded and optimal
+            x = Result.x;
+            f = osense*Result.objval;
         elseif (stat == 103 || stat == 3)
             solStat = 0; % Integer infeas
         elseif (stat == 118 || stat == 119 || stat == 2)