import json
from os import path
import warnings
import numpy
import six
from chainer import reporter
import chainer.serializer as serializer_module
from chainer.training import extension
import chainer.training.trigger as trigger_module
try:
from matplotlib import pyplot as plot
_available = True
except (ImportError, TypeError):
_available = False
def _check_available():
if not _available:
warnings.warn('matplotlib is not installed on your environment, '
'so nothing will be plotted at this time. '
'Please install matplotlib to plot figures.\n\n'
' $ pip install matplotlib\n')
[docs]class PlotReport(extension.Extension):
"""Trainer extension to output plots.
This extension accumulates the observations of the trainer to
:class:`~chainer.DictSummary` at a regular interval specified by a supplied
trigger, and plot a graph with using them.
There are two triggers to handle this extension. One is the trigger to
invoke this extension, which is used to handle the timing of accumulating
the results. It is set to ``1, 'iteration'`` by default. The other is the
trigger to determine when to emit the result. When this trigger returns
True, this extension appends the summary of accumulated values to the list
of past summaries, and writes the list to the log file. Then, this
extension makes a new fresh summary object which is used until the next
time that the trigger fires.
It also adds ``'epoch'`` and ``'iteration'`` entries to each result
dictionary, which are the epoch and iteration counts at the output.
.. warning::
If your environment needs to specify a backend of matplotlib
explicitly, please call ``matplotlib.use`` before importing Chainer.
For example:
.. code-block:: python
import matplotlib
matplotlib.use('Agg')
import chainer
Then, once ``chainer.training.extensions`` is imported,
``matplotlib.use`` will have no effect.
For the details, please see here:
http://matplotlib.org/faq/usage_faq.html#what-is-a-backend
Args:
y_keys (iterable of strs): Keys of values regarded as y. If this is
None, nothing is output to the graph.
x_key (str): Keys of values regarded as x. The default value is
'iteration'.
trigger: Trigger that decides when to aggregate the result and output
the values. This is distinct from the trigger of this extension
itself. If it is a tuple in the form ``<int>, 'epoch'`` or ``<int>,
'iteration'``, it is passed to :class:`IntervalTrigger`.
postprocess: Callback to postprocess the result dictionaries. Figure
object, Axes object, and all plot data are passed to this callback
in this order. This callback can modify the figure.
file_name (str): Name of the figure file under the output directory.
It can be a format string.
marker (str): The marker used to plot the graph. Default is ``'x'``. If
``None`` is given, it draws with no markers.
grid (bool): Set the axis grid on if True. Default is True.
"""
def __init__(self, y_keys, x_key='iteration', trigger=(1, 'epoch'),
postprocess=None, file_name='plot.png', marker='x',
grid=True):
_check_available()
self._x_key = x_key
if isinstance(y_keys, str):
y_keys = (y_keys,)
self._y_keys = y_keys
self._trigger = trigger_module.get_trigger(trigger)
self._file_name = file_name
self._marker = marker
self._grid = grid
self._postprocess = postprocess
self._init_summary()
self._data = {k: [] for k in y_keys}
@staticmethod
def available():
_check_available()
return _available
def __call__(self, trainer):
if not _available:
return
keys = self._y_keys
observation = trainer.observation
summary = self._summary
if keys is None:
summary.add(observation)
else:
summary.add({k: observation[k] for k in keys if k in observation})
if self._trigger(trainer):
stats = self._summary.compute_mean()
stats_cpu = {}
for name, value in six.iteritems(stats):
stats_cpu[name] = float(value) # copy to CPU
updater = trainer.updater
stats_cpu['epoch'] = updater.epoch
stats_cpu['iteration'] = updater.iteration
x = stats_cpu[self._x_key]
data = self._data
for k in keys:
if k in stats_cpu:
data[k].append((x, stats_cpu[k]))
f = plot.figure()
a = f.add_subplot(111)
a.set_xlabel(self._x_key)
if self._grid:
a.grid()
for k in keys:
xy = data[k]
if len(xy) == 0:
continue
xy = numpy.array(xy)
a.plot(xy[:, 0], xy[:, 1], marker=self._marker, label=k)
if a.has_data():
if self._postprocess is not None:
self._postprocess(f, a, summary)
l = a.legend(bbox_to_anchor=(1.05, 1), loc=2, borderaxespad=0.)
f.savefig(path.join(trainer.out, self._file_name),
bbox_extra_artists=(l,), bbox_inches='tight')
plot.close()
self._init_summary()
def serialize(self, serializer):
if isinstance(serializer, serializer_module.Serializer):
serializer('_plot_{}'.format(self._file_name),
json.dumps(self._data))
else:
self._data = json.loads(
serializer('_plot_{}'.format(self._file_name), ''))
def _init_summary(self):
self._summary = reporter.DictSummary()