models.callbacks
– Callbacks for track and viz LDA train process¶
Callbacks can be used to observe the training process.
Since training in huge corpora can be time consuming, we want to offer the users some insight into the process, in real time. In this way, convergence issues or other potential problems can be identified early in the process, saving precious time and resources.
The metrics exposed through this module can be used to construct Callbacks, which will be called at specific points in the training process, such as “epoch starts” or “epoch finished”. These metrics can be used to assess mod’s convergence or correctness, for example to save the model, visualize intermediate results, or anything else.
Usage examples¶
To implement a Callback, inherit from this base class and override one or more of its methods.
Create a callback to save the training model after each epoch
>>> from gensim.test.utils import get_tmpfile
>>> from gensim.models.callbacks import CallbackAny2Vec
>>>
>>>
>>> class EpochSaver(CallbackAny2Vec):
... '''Callback to save model after each epoch.'''
...
... def __init__(self, path_prefix):
... self.path_prefix = path_prefix
... self.epoch = 0
...
... def on_epoch_end(self, model):
... output_path = get_tmpfile('{}_epoch{}.model'.format(self.path_prefix, self.epoch))
... model.save(output_path)
... self.epoch += 1
...
Create a callback to print progress information to the console:
>>> class EpochLogger(CallbackAny2Vec):
... '''Callback to log information about training'''
...
... def __init__(self):
... self.epoch = 0
...
... def on_epoch_begin(self, model):
... print("Epoch #{} start".format(self.epoch))
...
... def on_epoch_end(self, model):
... print("Epoch #{} end".format(self.epoch))
... self.epoch += 1
...
>>>
>>> epoch_logger = EpochLogger()
>>> w2v_model = Word2Vec(common_texts, epochs=5, vector_size=10, min_count=0, seed=42, callbacks=[epoch_logger])
Epoch #0 start
Epoch #0 end
Epoch #1 start
Epoch #1 end
Epoch #2 start
Epoch #2 end
Epoch #3 start
Epoch #3 end
Epoch #4 start
Epoch #4 end
Create and bind a callback to a topic model. This callback will log the perplexity metric in real time:
>>> from gensim.models.callbacks import PerplexityMetric
>>> from gensim.models.ldamodel import LdaModel
>>> from gensim.test.utils import common_corpus, common_dictionary
>>>
>>> # Log the perplexity score at the end of each epoch.
>>> perplexity_logger = PerplexityMetric(corpus=common_corpus, logger='shell')
>>> lda = LdaModel(common_corpus, id2word=common_dictionary, num_topics=5, callbacks=[perplexity_logger])

class
gensim.models.callbacks.
Callback
(metrics)¶ Bases:
object
A class representing routines called reactively at specific phases during trained.
These can be used to log or visualize the training progress using any of the metric scores developed before. The values are stored at the end of each training epoch. The following metric scores are currently available:
 Parameters
metrics (list of
Metric
) – The list of metrics to be reported by the callback.

on_epoch_end
(epoch, topics=None)¶ Report the current epoch’s metric value.
Called at the end of each training iteration.
 Parameters
epoch (int) – The epoch that just ended.
topics (list of list of str, optional) – List of tokenized topics. This is required for the coherence metric.
 Returns
Mapping from metric names to their values. The type of each value depends on the metric type, for example
DiffMetric
computes a matrix whileConvergenceMetric
computes a float. Return type
dict of (str, object)

set_model
(model)¶ Save the model instance and initialize any required variables which would be updated throughout training.
 Parameters
model (
BaseTopicModel
) – The model for which the training will be reported (logged or visualized) by the callback.

class
gensim.models.callbacks.
CallbackAny2Vec
¶ Bases:
object
Base class to build callbacks for
Word2Vec
& subclasses.Callbacks are used to apply custom functions over the model at specific points during training (epoch start, batch end etc.). This is a base class and its purpose is to be inherited by custom Callbacks that implement one or more of its methods (depending on the point during training where they want some action to be taken).
See examples at the module level docstring for how to define your own callbacks by inheriting from this class.

on_batch_begin
(model)¶ Method called at the start of each batch.
 Parameters
model (
Word2Vec
or subclass) – Current model.

on_batch_end
(model)¶ Method called at the end of each batch.
 Parameters
model (
Word2Vec
or subclass) – Current model.

on_epoch_begin
(model)¶ Method called at the start of each epoch.
 Parameters
model (
Word2Vec
or subclass) – Current model.

on_epoch_end
(model)¶ Method called at the end of each epoch.
 Parameters
model (
Word2Vec
or subclass) – Current model.


class
gensim.models.callbacks.
CoherenceMetric
(corpus=None, texts=None, dictionary=None, coherence=None, window_size=None, topn=10, logger=None, viz_env=None, title=None)¶ Bases:
gensim.models.callbacks.Metric
Metric class for coherence evaluation.
See also
 Parameters
corpus ({iterable of list of (int, float), scipy.sparse.csc}, optional) – Stream of document vectors or sparse matrix of shape (num_documents, num_terms).
texts (list of char (str of length 1), optional) – Tokenized texts needed for coherence models that use sliding window based probability estimator.
dictionary (
Dictionary
, optional) – Gensim dictionary mapping from integer IDs to words, needed to create corpus. If model.id2word is present, this is not needed. If both are provided, dictionary will be used.coherence ({'u_mass', 'c_v', 'c_uci', 'c_npmi'}, optional) – Coherence measure to be used. ‘c_uci’ is also known as ‘c_pmi’ in the literature. For ‘u_mass’, the corpus MUST be provided. If texts is provided, it will be converted to corpus using the dictionary. For ‘c_v’, ‘c_uci’ and ‘c_npmi’, texts MUST be provided. Corpus is not needed.
window_size (int, optional) –
Size of the window to be used for coherence measures using boolean sliding window as their probability estimator. For ‘u_mass’ this doesn’t matter. If ‘None’, the default window sizes are used which are:
c_v  110
c_uci  10
c_npmi  10
topn (int, optional) – Number of top words to be extracted from each topic.
logger ({'shell', 'visdom'}, optional) – Monitor training process using one of the available methods. ‘shell’ will print the coherence value in the active shell, while ‘visdom’ will visualize the coherence value with increasing epochs using the Visdom visualization framework.
viz_env (object, optional) – Visdom environment to use for plotting the graph. Unused.
title (str, optional) – Title of the graph plot in case logger == ‘visdom’. Unused.

get_value
(**kwargs)¶ Get the coherence score.
 Parameters
**kwargs –
Key word arguments to override the object’s internal attributes. One of the following parameters are expected:
model  pretrained topic model of type
LdaModel
, or one of its wrappers, such asLdaMallet
orLdaVowpalWabbit
.topics  list of tokenized topics.
 Returns
The coherence score.
 Return type
float

set_parameters
(**parameters)¶ Set the metric parameters.
 Parameters
**parameters – Keyword arguments to override the object’s internal attributes.

class
gensim.models.callbacks.
ConvergenceMetric
(distance='jaccard', num_words=100, n_ann_terms=10, diagonal=True, annotation=False, normed=True, logger=None, viz_env=None, title=None)¶ Bases:
gensim.models.callbacks.Metric
Metric class for convergence evaluation.
 Parameters
distance ({'kullback_leibler', 'hellinger', 'jaccard'}, optional) – Measure used to calculate difference between any topic pair.
num_words (int, optional) – The number of most relevant words used if distance == ‘jaccard’. Also used for annotating topics.
n_ann_terms (int, optional) – Max number of words in intersection/symmetric difference between topics. Used for annotation.
diagonal (bool, optional) – Whether we need the difference between identical topics (the diagonal of the difference matrix).
annotation (bool, optional) – Whether the intersection or difference of words between two topics should be returned.
normed (bool, optional) – Whether the matrix should be normalized or not.
logger ({'shell', 'visdom'}, optional) – Monitor training process using one of the available methods. ‘shell’ will print the coherence value in the active shell, while ‘visdom’ will visualize the coherence value with increasing epochs using the Visdom visualization framework.
viz_env (object, optional) – Visdom environment to use for plotting the graph. Unused.
title (str, optional) – Title of the graph plot in case logger == ‘visdom’. Unused.

get_value
(**kwargs)¶ Get the sum of each element in the difference matrix between each pair of topics in two topic models.
A small difference between the partially trained models produced by subsequent training iterations can indicate that the model has stopped significantly improving and has therefore converged to a local or global optimum.
 Parameters
**kwargs – Key word arguments to override the object’s internal attributes. Two models of type
LdaModel
or its wrappers are expected using the keys model and other_model. Returns
The sum of the difference matrix between two trained topic models (usually the same model after two subsequent training iterations).
 Return type
float

set_parameters
(**parameters)¶ Set the metric parameters.
 Parameters
**parameters – Keyword arguments to override the object’s internal attributes.

class
gensim.models.callbacks.
DiffMetric
(distance='jaccard', num_words=100, n_ann_terms=10, diagonal=True, annotation=False, normed=True, logger=None, viz_env=None, title=None)¶ Bases:
gensim.models.callbacks.Metric
Metric class for topic difference evaluation.
 Parameters
distance ({'kullback_leibler', 'hellinger', 'jaccard'}, optional) – Measure used to calculate difference between any topic pair.
num_words (int, optional) – The number of most relevant words used if distance == ‘jaccard’. Also used for annotating topics.
n_ann_terms (int, optional) – Max number of words in intersection/symmetric difference between topics. Used for annotation.
diagonal (bool, optional) – Whether we need the difference between identical topics (the diagonal of the difference matrix).
annotation (bool, optional) – Whether the intersection or difference of words between two topics should be returned.
normed (bool, optional) – Whether the matrix should be normalized or not.
logger ({'shell', 'visdom'}, optional) – Monitor training process using one of the available methods. ‘shell’ will print the coherence value in the active shell, while ‘visdom’ will visualize the coherence value with increasing epochs using the Visdom visualization framework.
viz_env (object, optional) – Visdom environment to use for plotting the graph. Unused.
title (str, optional) – Title of the graph plot in case logger == ‘visdom’. Unused.

get_value
(**kwargs)¶ Get the difference between each pair of topics in two topic models.
 Parameters
**kwargs – Key word arguments to override the object’s internal attributes. Two models of type
ldamodelLdaModel
or its wrappers are expected using the keys model and other_model. Returns
np.ndarray of shape (model.num_topics, other_model.num_topics) – Matrix of differences between each pair of topics.
np.ndarray of shape (model.num_topics, other_model.num_topics, 2), optional – Annotation matrix where for each pair we include the word from the intersection of the two topics, and the word from the symmetric difference of the two topics. Only included if annotation == True.

set_parameters
(**parameters)¶ Set the metric parameters.
 Parameters
**parameters – Keyword arguments to override the object’s internal attributes.

class
gensim.models.callbacks.
Metric
¶ Bases:
object
Base Metric class for topic model evaluation metrics.
Concrete implementations include:

get_value
()¶ Get the metric’s value at this point in time.
Warning
The user must provide a concrete implementation for this method for every subclass of this class.
See also
gensim.models.callbacks.CoherenceMetric.get_value()
,gensim.models.callbacks.PerplexityMetric.get_value()
,gensim.models.callbacks.DiffMetric.get_value()
,gensim.models.callbacks.ConvergenceMetric.get_value()
 Returns
The metric’s type depends on what exactly it measures. In the simplest case it might be a real number corresponding to an error estimate. It could however be anything else that is useful to report or visualize.
 Return type
object

set_parameters
(**parameters)¶ Set the metric parameters.
 Parameters
**parameters – Keyword arguments to override the object’s internal attributes.


class
gensim.models.callbacks.
PerplexityMetric
(corpus=None, logger=None, viz_env=None, title=None)¶ Bases:
gensim.models.callbacks.Metric
Metric class for perplexity evaluation.
 Parameters
corpus ({iterable of list of (int, float), scipy.sparse.csc}, optional) – Stream of document vectors or sparse matrix of shape (num_documents, num_terms).
logger ({'shell', 'visdom'}, optional) – Monitor training process using one of the available methods. ‘shell’ will print the perplexity value in the active shell, while ‘visdom’ will visualize the coherence value with increasing epochs using the Visdom visualization framework.
viz_env (object, optional) – Visdom environment to use for plotting the graph. Unused.
title (str, optional) – Title of the graph plot in case logger == ‘visdom’. Unused.

get_value
(**kwargs)¶ Get the coherence score.

set_parameters
(**parameters)¶ Set the metric parameters.
 Parameters
**parameters – Keyword arguments to override the object’s internal attributes.