Added containsNaN() method to GridProperty

opm/parser/eclipse/EclipseState/Grid/GridProperty.cpp

@@ -32,4 +32,25 @@ void GridProperty<double>::setDataPoint(size_t sourceIdx, size_t targetIdx, Opm:
     m_data[targetIdx] = deckItem->getSIDouble(sourceIdx);
 }
 
+
+template<>
+bool GridProperty<double>::containsNaN( ) {
+    bool return_value = false;
+    size_t size = m_data.size();
+    size_t index = 0;    
+    while (true) {
+        if (std::isnan(m_data[index])) {
+            return_value = true;
+            break;
+        }
+    
+        index++;
+        if (index == size)
+            break;
+    }
+    return return_value;
 }
+}
+
+
+