Peak-to-peak amplitude in Comsol 4.3a ?

Hi

I need to evaluate the peak-to-peak (pk-pk) amplitude of a voltage, which means the difference between the maximum positive and the maximum negative of a waveform. Are there any predefined function to do so in Comsol 4.3a, please?

Or are there, at least, any predefined functions to calculate max postive (highest amplitude value) and max negative (lowest amplitude value, which can be negative) of a waveform ? That would be a help too.

I searched the docs and the forums but to no avail.

Thanks very much