Fix date for long simulation times

opm/simulators/timestepping/SimulatorTimer.cpp

@@ -114,7 +114,9 @@ namespace Opm
 
     boost::posix_time::ptime SimulatorTimer::currentDateTime() const
     {
-        return startDateTime() + boost::posix_time::seconds( (int) simulationTimeElapsed());
+        // boost uses only 32 bit long for seconds. But 64 bit for milliseconds
+        // as a work around for very large timess we just use milliseconds
+        return startDateTime() + boost::posix_time::milliseconds( simulationTimeElapsed() / Opm::prefix::milli);
     }
 
     /// Total time.