scikit-learn/scikit-learn — pull request #2220 by pprett (2013-07-25 09:54:26+00:00)
Title: [MRG] Gbrt verbose output

I refactored the verbose output of GBRT. The output contains less boilerplate text and is nicer aligned.
It now also reports OOB improvement and estimated time (in seconds or minutes).
Here is an example on covertype using ``verbose=1``:

Iter Train Loss Estimated Time
1 1.2980 7.89m
2 1.2814 7.82m
3 1.2378 7.95m
4 1.2234 8.10m
5 1.1893 7.94m
6 1.1820 7.92m
7 1.1756 7.95m
8 1.1660 7.74m
9 1.1394 7.81m
10 1.1157 7.85m
20 1.0111 7.63m
30 0.9602 6.70m
40 0.9354 5.66m
50 0.9124 4.64m
60 0.8979 3.65m
70 0.8859 2.72m
80 0.8762 1.81m
90 0.8691 53.82s
100 0.8599 0.00s

the old output for ``verbose==1`` was just a ``'.'`` for each iteration. Using ``verbose>1`` on **master** gives the following output::

built tree 1 of 100, train score = 1.297973e+00
built tree 2 of 100, train score = 1.281386e+00
built tree 3 of 100, train score = 1.237790e+00

For ``verbose==1`` it will print iterations with modulo is zero.
For ``verbose>1`` it will print each iteration.

There are now test for verbose output.