return more precise result in dd equation solver

src/storm/modelchecker/results/HybridQuantitativeCheckResult.cpp

@@ -115,6 +115,9 @@ namespace storm {
                             }
                             out << valuationValuePair.second;
                         }
+                        if (symbolicStates.getNonZeroCount() != this->symbolicValues.getNonZeroCount()) {
+                            out << ", 0";
+                        }
                     }
                 }
                 if (!this->explicitStates.isZero()) {

src/storm/modelchecker/results/SymbolicQuantitativeCheckResult.cpp

@@ -75,6 +75,9 @@ namespace storm {
                         }
                         out << valuationValuePair.second;
                     }
+                    if (states.getNonZeroCount() != this->values.getNonZeroCount()) {
+                        out << ", 0";
+                    }
                 }
                 out << "}";
             } else {

src/storm/solver/SymbolicLinearEquationSolver.cpp

@@ -55,10 +55,7 @@ namespace storm {
                 // Now check if the process already converged within our precision.
                 converged = xCopy.equalModuloPrecision(tmp, precision, relative);
 
-                // If the method did not converge yet, we prepare the x vector for the next iteration.
-                if (!converged) {
-                    xCopy = tmp;
-                }
+                xCopy = tmp;
                 
                 // Increase iteration count so we can abort if convergence is too slow.
                 ++iterationCount;