[MaL] Compress eigen matrix before solve.

MathLib/LinAlg/Eigen/EigenLinearSolver.cpp

@@ -37,6 +37,8 @@ public:
     void solve(EigenVector::RawVectorType &b, EigenVector::RawVectorType &x, EigenOption &/*opt*/) override
     {
         INFO("-> solve");
+        if (!_A.isCompressed())
+            _A.makeCompressed();
         _solver.compute(_A);
         if(_solver.info()!=Eigen::Success) {
             ERR("Failed during Eigen linear solver initialization");
@@ -70,6 +72,8 @@ public:
         INFO("-> solve");
         _solver.setTolerance(opt.error_tolerance);
         _solver.setMaxIterations(opt.max_iterations);
+        if (!_A.isCompressed())
+            _A.makeCompressed();
         _solver.compute(_A);
         if(_solver.info()!=Eigen::Success) {
             ERR("Failed during Eigen linear solver initialization");