Dear all, I am running a Firedrake code in parallel with 4 cores, in which I save the maximal value of the amplitude of the wave at each time, with the command: max_eta = max(eta.dat.data) Eta_file.write('%-10s %-10s %-10s\n' % (t,'', eta_max)) But when opening the .txt file, I notice two issues: - the data are not saved continuously: time goes from 0 to 100 (let's say) and then starts from 90 again; - the values of max_eta are not the maximal values of eta, except at the beginning. So it looks like the function max takes the maximum value of eta only in one subdomain, so that after the wave has crossed the subdomain, the maximal value of eta goes back to the depth of rest value. How can I force this command to be applied on the full domain, even if the code is run in parallel? Thanks, Floriane