Fixed dangling reference when using Eigen matrix views repeatedly.

Optima/EchelonizerW.cpp

@@ -21,6 +21,7 @@
 #include <Optima/Exception.hpp>
 #include <Optima/EchelonizerExtended.hpp>
 #include <Optima/Utils.hpp>
+#include <Optima/Macros.hpp>
 
 namespace Optima {
 
@@ -90,19 +91,7 @@ struct EchelonizerW::Impl
         const auto nb = echelonizer.numBasicVariables();
         const auto nn = echelonizer.numNonBasicVariables();
 
-        //=============================================================================================================
-        // WARNING:
-        //=============================================================================================================
-        // For some reason, the commented line below does not play correctly with
-        // eigen commit 7b35638ddb99a0298c5d3450de506a8e8e0203d3 in Windows with Release mode.
-        // This problem does not exist in Linux and macOS, and also in Windows with Debug mode.
-        // The pytest tests fail with error message like this:
-        //   Windows fatal exception: access violation
-        //   Current thread 0x00002544 (most recent call first):
-        //   File "C:\Users\allan\codes\optima\tests\testing\utils\matrices.py", line 156 in createMatrixViewRWQ
-        // The solution was to avoid creating the topRows reference from the returned reference in echelonizer.R().
-        //=============================================================================================================
-        // const auto Rb = echelonizer.R().topRows(nb);  // WARNING: This
+        // const auto Rb = echelonizer.R().topRows(nb); // WARNING: This creates dangling references. 
         const auto R = echelonizer.R();
         const auto Rb = R.topRows(nb);
 
@@ -155,7 +144,8 @@ struct EchelonizerW::Impl
         const auto nb = echelonizer.numBasicVariables();
         const auto nn = echelonizer.numNonBasicVariables();
 
-        const auto Rb   = echelonizer.R().topRows(nb);
+        const auto R   = echelonizer.R();
+        const auto Rb  = R.topRows(nb);
         const auto Sbn = S.topLeftCorner(nb, nn);
         const auto Sbp = S.topRightCorner(nb, np);
         const auto jbn = echelonizer.Q();