Cumulative sum ???

Is it possible to achieve (within comsol) a cumulative sum of a time varying data. Here I'm interested in the calculation of the cumulate mass of water going through a porous media. It is quite easy to get the transient evolution of mass flow rate, but I do not manage to get the cumulative mass flow unless exporting data to Matlab.

Any sugestions are welcome.

Best regards,

D. L.