Need help? Have a feature request? Please check out the
tethne-users group
.
Source code for tethne.model.corpus.mallet
"""
Classes and methods related to the :class:`.MALLETModelManager`\.
"""
import os, sys, re, shutil, tempfile, subprocess, csv, platform, inspect
from collections import defaultdict
from networkx import Graph
PYTHON_3 = sys.version_info[0] == 3
if PYTHON_3:
unicode = str
import logging
logging.basicConfig()
logger = logging.getLogger('mallet')
logger.setLevel('ERROR')
from tethne import write_documents, Feature, FeatureSet
from tethne.model import Model
from tethne.model.corpus import LDAMixin
# Determine path to MALLET.
TETHNE_PATH = os.path.join(os.path.dirname(os.path.abspath(inspect.stack()[0][1])), '..', '..')
MALLET_PATH = os.path.join(TETHNE_PATH, 'bin', 'mallet-2.0.7')
import sys
if sys.version_info[0] > 2:
xrange = range
[docs]class LDAModel(Model, LDAMixin):
"""
Generates a :class:`.LDAModel` from a :class:`.Corpus` using
`MALLET <http://mallet.cs.umass.edu/>`_.
The :class:`.Corpus` should already contain at least one featurset,
indicated by the `feature` parameter, such as wordcounts. You may
specify two working directories: `temppath` should be a working
directory that will contain intermediate files (e.g. documents, data
files, metadata), while `outpath` will contain the final model and any
plots generated during the modeling process. If `temppath` is not
provided, generates and uses a system temporary directory.
Tethne comes bundled with a recent version of MALLET. If you would
rather use your own install, you can do so by providing the
`mallet_path` parameter. This should point to the directory containing
``/bin/mallet``.
.. autosummary::
:nosignatures:
topic_over_time
Parameters
----------
D : :class:`.Corpus`
feature : str
Key from D.features containing wordcounts (or whatever
you want to model with).
outpath : str
Path to output directory.
temppath : str
Path to temporary directory.
mallet_path : str
Path to MALLET install directory (contains bin/mallet).
Examples
--------
Starting with some JSTOR DfR data (with wordcounts), a typical workflow
might look something like this:
.. code-block:: python
>>> from nltk.corpus import stopwords # 1. Get stoplist.
>>> stoplist = stopwords.words()
>>> from tethne.readers import dfr # 2. Build Corpus.
>>> C = dfr.corpus_from_dir('/path/to/DfR/datasets', 'uni', stoplist)
>>> def filt(s, C, DC): # 3. Filter wordcounts.
... if C > 3 and DC > 1 and len(s) > 3:
... return True
... return False
>>> C.filter_features('wordcounts', 'wc_filtered', filt)
>>> from tethne.model import MALLETModelManager # 4. Get Manager.
>>> outpath = '/path/to/my/working/directory'
>>> mallet = '/Applications/mallet-2.0.7'
>>> M = MALLETModelManager(C, 'wc_filtered', outpath, mallet_path=mallet)
>>> M.prep() # 5. Prep model.
>>> model = M.build(Z=50, max_iter=300) # 6. Build model.
>>> model # (may take awhile)
<tethne.model.corpus.ldamodel.LDAModel at 0x10bfac710>
A plot showing the log-likelihood/topic over modeling iterations should be
generated in your `outpath`. For example:
.. figure:: _static/images/ldamodel_LL.png
:width: 400
:align: center
Behind the scenes, the :func:`.prep` procedure generates a plain-text corpus
file at `temppath`, along with a metadata file. MALLET's ``import-file``
procedure is then called, which translates the corpus into MALLET's internal
format (also stored at the `temppath`).
The :func:`.build` procedure then invokes MALLET's ``train-topics``
procedure. This step may take a considerable amount of time, anywhere from
a few minutes (small corpus, few topics) to a few hours (large corpus, many
topics).
For a :class:`.Corpus` with a few thousand :class:`.Paper`\s, 300 - 500
iterations is often sufficient to achieve convergence for 20-100 topics.
Once the :class:`.LDAModel` is built, you can access its methods directly.
See full method descriptions in :class:`.LDAModel`\.
For more information about topic modeling with MALLET see
`this tutorial <http://programminghistorian.org/lessons/topic-modeling-and-mallet>`_.
"""
mallet_path = MALLET_PATH
@staticmethod
[docs] def from_mallet(corpus, featureset_name, wt_path, dt_path, model_path):
model = LDAModel(corpus, featureset_name=featureset_name,
nodelete=True, # So that it doesn't discard your files when you're done.
prep=False, # Skips building the corpus and calling MALLET's import function.
wt=wt_path,
dt=dt_path,
om=model_path)
model.load()
return model
def __init__(self, *args, **kwargs):
self.mallet_bin = os.path.join(self.mallet_path, "bin", "mallet")
if platform.system() == 'Windows':
self.mallet_bin += '.bat'
os.environ['MALLET_HOME'] = self.mallet_path
super(LDAModel, self).__init__(*args, **kwargs)
if not hasattr(self, 'dt'):
self.dt = os.path.join(self.temp, "dt.dat")
if not hasattr(self, 'wt'):
self.wt = os.path.join(self.temp, "wt.dat")
if not hasattr(self, 'om'):
self.om = os.path.join(self.temp, "model.mallet")
def _generate_corpus(self):
"""
Writes a corpus to disk amenable to MALLET topic modeling.
"""
target = self.temp + 'mallet'
paths = write_documents(self.corpus, target, self.featureset_name,
['date', 'title'])
self.corpus_path, self.metapath = paths
self._export_corpus()
def _export_corpus(self):
"""
Calls MALLET's `import-file` method.
"""
# bin/mallet import-file --input /Users/erickpeirson/mycorpus_docs.txt
# --output mytopic-input.mallet --keep-sequence --remove-stopwords
if not os.path.exists(self.mallet_bin):
raise IOError("MALLET path invalid or non-existent.")
self.input_path = os.path.join(self.temp, "input.mallet")
exit = subprocess.call([
self.mallet_bin,
'import-file',
'--input', self.corpus_path,
'--output', self.input_path,
'--keep-sequence', # Required for LDA.
'--remove-stopwords'], # Probably redundant.
env={"MALLET_HOME": self.mallet_path})
if exit != 0:
msg = "MALLET import-file failed with exit code {0}.".format(exit)
raise RuntimeError(msg)
[docs] def run(self, **kwargs):
"""
Calls MALLET's `train-topic` method.
"""
#$ bin/mallet train-topics --input mytopic-input.mallet
#> --num-topics 100
#> --output-doc-topics /Users/erickpeirson/doc_top
#> --word-topic-counts-file /Users/erickpeirson/word_top
#> --output-topic-keys /Users/erickpeirson/topic_keys
if not os.path.exists(self.mallet_bin):
raise IOError("MALLET path invalid or non-existent.")
for attr in ['Z', 'max_iter']:
if not hasattr(self, attr):
raise AttributeError('Please set {0}'.format(attr))
self.ll = []
self.num_iters = 0
logger.debug('run() with k={0} for {1} iterations'.format(self.Z, self.max_iter))
prog = re.compile(u'\<([^\)]+)\>')
ll_prog = re.compile(r'(\d+)')
p = subprocess.Popen([
self.mallet_bin,
'train-topics',
'--input', self.input_path,
'--num-topics', unicode(self.Z),
'--num-iterations', unicode(self.max_iter),
'--output-doc-topics', self.dt,
'--word-topic-counts-file', self.wt,
'--output-model', self.om],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
env={"MALLET_HOME": self.mallet_path})
# Handle output of MALLET in real time.
while p.poll() is None:
l = p.stderr.readline()
# Keep track of LL/topic.
try:
this_ll = float(re.findall(u'([-+]\d+\.\d+)', l)[0])
self.ll.append(this_ll)
except IndexError: # Not every line will match.
pass
# Keep track of modeling progress.
try:
this_iter = float(prog.match(l).groups()[0])
progress = int(100. * this_iter/self.max_iter)
print 'Modeling progress: {0}%.\r'.format(progress),
except AttributeError: # Not every line will match.
pass
self.num_iters += self.max_iter
self.load()
[docs] def load(self, **kwargs):
self._read_theta(kwargs.get('dt', self.dt))
self._read_phi(kwargs.get('wt', self.wt))
def _read_theta(self, dt):
"""
Used by :func:`.from_mallet` to reconstruct theta posterior
distributions.
Returns
-------
td : Numpy array
Rows are documents, columns are topics. Rows sum to ~1.
"""
self.theta = mallet_to_theta_featureset(dt)
self.corpus.features['topics'] = self.theta
return self.theta
def _read_phi(self, wt):
"""
Used by :func:`.from_mallet` to reconstruct phi posterior distributions.
Returns
-------
wt : Numpy array
Rows are topics, columns are words. Rows sum to ~1.
"""
self.phi, self.vocabulary = mallet_to_phi_featureset(wt)
[docs]def mallet_to_theta_featureset(dt_path):
"""
Generate a :class:`.FeatureSet` describing document-topic assignments from a
MALLET document-topic output file.
Parameters
----------
dt_path : str
Full path to the document-topic data file created by MALLET.
Returns
-------
theta : :class:`.FeatureSet`
"""
theta = FeatureSet()
with open(dt_path, "rb") as f:
i = -1
reader = csv.reader(f, delimiter='\t')
for line in reader:
i += 1
if i == 0:
continue # Avoid header row.
d, id, t = int(line[0]), unicode(line[1]), line[2:]
feature = Feature([(int(t[i]), float(t[i + 1]))
for i in xrange(0, len(t) - 1, 2)])
theta.add(id, feature)
return theta
[docs]def mallet_to_phi_featureset(wt_path):
"""
Generate a :class:`.FeatureSet` describing word-topic assignments from a
MALLET word-topic output file.
Parameters
----------
wt_path : str
Full path to the word-topic data file created by MALLET.
Returns
-------
phi : :class:`.FeatureSet`
"""
vocabulary = {}
phi_features = {}
# TODO: make this encoding-safe.
with open(wt_path, "r") as f:
reader = csv.reader(f, delimiter=' ')
topics = defaultdict(list)
for line in reader:
w, term = int(line[0]), unicode(line[1])
vocabulary[w] = term
for l in line[2:]:
k, c = l.split(':') # Topic and assignment count.
topics[int(k)].append((w, int(c)))
for k, data in topics.iteritems():
nfeature = Feature(data).norm
phi_features[k] = nfeature
return FeatureSet(phi_features), vocabulary
