more timing stats

[stevengj]

Continuation of #927. If fields::verbose() is set, then it prints out timing values from every process.

[oskooi]

$ mpirun -np 3 python ~/meep/python/examples/refl-angular.py
...
...
Field time usage:
        connecting chunks: 0.000521342 s +/- 1.58173e-05 s
            time stepping: 2.46249 s +/- 0.013184 s
            communicating: 0.91695 s +/- 0.0118404 s
     Fourier transforming: 0.248497 s +/- 0.338284 s
          everything else: 2.76524 s +/- 0.339444 s


Field time usage for all processes:
        connecting chunks: 0.000524998, 0.000504017, 0.000535011
            time stepping: 2.44917, 2.47553, 2.46278
          copying borders: 0, 0, 0
            communicating: 0.930335, 0.907844, 0.91267
        outputting fields: 0, 0, 0
     Fourier transforming: 0.639113, 0.0527964, 0.0535817
                      MPB: 0, 0, 0
        getting farfields: 0, 0, 0
          everything else: 2.37331, 2.9575, 2.96492

[stevengj]

That looks good — note that the data is only printed to six significant digits, if you take this data and compute std in numpy or whatever, it will only reproduce the computed std dev approximately (the last digit will generally not match).