As a part of the assignment, I am asked to do topic modeling using LDA and visualize the words that come under the top 3 topics as shown in the below screenshot 1. However, even after searching a lot I am not able to find any helpful resource that would help me achieve my goal. All resources about text visualization are pointed towards the word cloud, but my goal is not to use word cloud visualizations.
Required LDA topic visulization
Any help will be greatly appreciated.
If you use gensim to generate the LDA model (gensim.models.ldamodel.LdaModel()) you can use the following to easily visualize the key words related to each topic:
# Example of LDA model building:
lda_model = gensim.models.ldamodel.LdaModel(corpus=corpus,
id2word=id2word,
num_topics=20,
random_state=100,
update_every=1,
chunksize=100,
passes=10,
alpha='auto',
per_word_topics=True)
# Visualize keywords
print(lda_model.print_topics())
Also for better visualization I suggest you to use pyLDAvis through:
import pyLDAvis
import pyLDAvis.gensim
pyLDAvis.enable_notebook()
vis = pyLDAvis.gensim.prepare(lda_model, corpus, id2word)
vis
Where you feed your lda model, corpus and a dictionary mapping ids to tokens (id2word). Output:
Have a look at the example here for a detailed explanation:
https://www.machinelearningplus.com/nlp/topic-modeling-gensim-python/
Related
I was looking for some guidence on NER using medspacy. Aware of disease extraction using MedSpacy but the aim is to extract patient name from medical report using medspacy.
Text supposed to be :
patient:Jeromy, David (DOB)
Date range 2020 to 2022. Visited Dr Brian. Suffered from ...
This type of dataset is there, want to extract patient name from all the pages of medical reports using MedSpacy. I know target rules can be helpful but any clarified guidence will be appreciated.
Thanks & regards
If you find that the default SpaCy NER model is not sufficient, as it will not pick up names such as "Byrn, John", I have a couple of suggestions:
Train a custom NER component using SpaCy's Prodigy annotation tool, which you can use to easily label some examples of names. This is a rather simple task, so you can likely train a model with less than 100 diverse examples. Note: Prodigy is a paid tool, so see my other suggestions if you do not have access/are not willing to pay.
Train a custom NER component without Prodigy. Similar to the above approach, but slightly more involved. This Medium article provides a beginner-friendly introduction to doing so, and you can also refer to SpaCy's own documentation. You can provide SpaCy with some examples of texts and the entities you want extracted, like so:
TRAIN_DATA = [
('Patient: Byrn, John', {
'entities': [(9, 19, 'PERSON')]
}),
('John Byrn received 10mg of advil', {
'entities': [(0, 10, 'PERSON')]
})
]
Build rules based on existing SpaCy components. You can leverage existing SpaCy pipeline components (you don't necessarily need MedSpaCy for this), such as POS tagging and Dependency Parsing. For example, you can look for proper nouns in your documents to identify names. Check out the docs on POS tagging here.
Try other pretrained NER models. There may be other models that are better suited to your task. Check out other models on SpaCy Universe, or even better, on HuggingFaceHub, which contains some of the best models out there for every use case. Added bonus of HF Hub is that you can try out the models on each model model page, and assess the performance on some examples before you decide.
Hope this helps!
I am writing a small proof of concept where I turn a catalog into a json that has a url, and a label that explains the web page. I read this json in python, tokenize it and create a pad_sequences.
I need to then compare some free flow texts to find which index of the pad_sequences has the most words from the free flow text.
I am generating a pad_sequences() from the text too but not sure if I can somehow compare the two sequences for closeness?
Please help.
You can use cosine similarity or euclidean distance to compare two vectors.
https://www.tensorflow.org/api_docs/python/tf/keras/metrics/CosineSimilarity
https://www.tutorialexample.com/calculate-euclidean-distance-in-tensorflow-a-step-guide-tensorflow-tutorial/
For sequences you can make embedding to same lenght vector at first.
Let us assume that I have a set of document embeddings. (D)
Each of document embedding is consisting of N number of word vectors where each of these pre-trained vector has 300 dimensions.
The corpus would be represented as [D,N,300].
My question is that, what would be the best way to reduce [D,N,300] to [D,1, 300]. How should I represent the document in a single vector instead of N vectors?
Thank you in advance.
I would say that what you are looking for is doc2vec. Using this you can convert the whole document into a one, 300-dimensional vector. You can use it like this:
from gensim.test.utils import common_texts
from gensim.models.doc2vec import Doc2Vec, TaggedDocument
documents = [TaggedDocument(doc, [i]) for i, doc in enumerate(your_documents)]
model = Doc2Vec(documents, vector_size=300, window=2, min_count=1, workers=4)
This will train the model on your data and you will be able to represent each document with only one vector as you specified in the question.
You can run inferrance with:
vector = model.infer_vector(doc_words)
I hope this is helpful :)
It's fairly common and fairly (perhaps surprisingly) effective to simply average the word vectors.
Good question but all the answers will result in the some loss of information. The best way for you is to use a Bi-LSTM/GRU layer and provide your word embeddings as input to that layer. And take the output of last time step.
The output of last timestep will have all the contextual information of document both in forward and backward direction. And hence, this is the best way to get what you want as the model learns the representation.
Note that, the larger the document, the more loss of information.
how do you train a neural network to map from a vector representation, to one hot vectors? The example I'm interested in is where the vector representation is the output of a word2vec embedding, and I'd like to map onto the the individual words which were in the language used to train the embedding, so I guess this is vec2word?
In a bit more detail; if I understand correctly, a cluster of points in embedded space represents similar words. Thus if you sample from points in that cluster, and use it as the input to vec2word, the output should be a mapping to similar individual words?
I guess I could do something similar to an encoder-decoder, but does it have to be that complicated/use so many parameters?
There's this TensorFlow tutorial, how to train word2vec, but I can't find any help to do the reverse? I'm happy to do it using any deeplearning library, and it's OK to do it using sampling/probabilistic.
Thanks a lot for your help, Ajay.
One easiest thing that you can do is to use the nearest neighbor word. Given a query feature of an unknown word fq, and a reference feature set of known words R={fr}, then you can find out what is the nearest fr* for fq, and use the corresponding fr* word as fq's word.
I've using tensorflow to build word2vec model,reference here：https://github.com/tensorflow/tensorflow/blob/master/tensorflow/examples/tutorials/word2vec/word2vec_basic.py#L118
my question is that, how can i find top n similar words for a certain word.I know in gensim, I can save and load word2vec model,and then use model.most_similar to find what I want.but how in tensorflow and even more is there any way to save model in tensorflow since i find what i get is only an embedding vector,is that right?
I think as long as you have computed the weight vector for each token, then you can manipulate all the tokens in the vector space. You can simply calculate the cosine similarity between each vector and then sort by score. For your reference, you can look at the source code of most_similar method implemented in gensim word2vec model. Hope this helps.