Body: <p>I new in machine learning, especially in Conditional Random Fields (CRF).</p>
  
  <p>I have read several articles and papers and in there is always associated with HMM and sequences classification. I don't really understand mathematics, especially in the annoying formula. So I can't understand the process. Where I need to start to understand CRFs??</p>
  
  <p>I want to make an information extraction application using CRF Named Entity Recognition (NER).</p>
  
  <p>I got some tutorial for that: <a href="https://eli5.readthedocs.io/en/latest/tutorials/sklearn_crfsuite.html#training-data" rel="nofollow noreferrer">https://eli5.readthedocs.io/en/latest/tutorials/sklearn_crfsuite.html#training-data</a> </p>
  
  <p><strong>But</strong> I don't know the proses each step, like training proses, evaluation, and testing</p>
  
  <p>I use this code :</p>
  
  <pre><code>  data_frame = eli5.format_as_dataframes(
              eli5.explain_weights_sklearn_crfsuite(self.crf))
  </code></pre>
  
  <p><strong>Targets</strong>
  <a href="https://i.sstatic.net/bCHpg.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/bCHpg.png" alt="enter image description here"></a></p>
  
  <p><strong>Transition Features</strong>
  <a href="https://i.sstatic.net/jqlGi.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/jqlGi.png" alt="enter image description here"></a></p>
  
  <p>How to get that number ?</p>
  
  <p>and 1 more thing makes me confused:</p>
  
  <pre><code>crf = sklearn_crfsuite.CRF(
      algorithm='lbfgs',
      c1=0.1,
      c2=0.1,
      max_iterations=20,
      all_possible_transitions=False,
  )
  </code></pre>
  
  <p>What is the algorithm <code>lbfgs</code>? Is the CRF not an algorithm? Why do I need <code>lbfgs</code>? What is exactly a conditional random field?</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-07-14T11:17:20.047Z
Comments.Text: I will provide an answer later, but you will have to wait (unless someone provides an answer meanwhile). Anyway, it is ok to be confused when it comes to CRFs, especially if you don't have a solid mathematical background.
Comments.UserDisplayName: nbro
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-07-14T13:14:33.707Z
Comments.Text: okay, thank you for responding I really appreciate that @nbro
Comments.UserDisplayName: Faris Dewantoro
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-07-20T10:28:15.370Z
Comments.Text: heyy i still waiting your answer @nbro :(
Comments.UserDisplayName: Faris Dewantoro
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-07-20T10:42:51.750Z
Comments.Text: Hey! Sorry for having made you wait for a long time without warning you. CRFs involve a lot of concepts. So, a satisfactory will possibly be quite long, which would have required some time. Meanwhile, I couldn't have spent so much time to give this answer. I will try to give you an answer this weekend.
Comments.UserDisplayName: nbro
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-07-20T11:15:52.803Z
Comments.Text: @nbro Ok, i will waiting your answer :(
Comments.UserDisplayName: Faris Dewantoro
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-07-29T08:39:34.263Z
Comments.Text: @nbro hey :( i am still waiting
Comments.UserDisplayName: Faris Dewantoro
Tags: <machine-learning><natural-language-processing><definitions><probabilistic-graphical-models><conditional-random-field>
Title: What is a conditional random field?
UserDisplayName: Faris Dewantoro
ThreadText: # What is a conditional random field?
  
  (Asked by: username_0 on 2019-07-14)
  
  I new in machine learning, especially in Conditional Random Fields (CRF).
  
  I have read several articles and papers and in there is always associated with HMM and sequences classification. I don't really understand mathematics, especially in the annoying formula. So I can't understand the process. Where I need to start to understand CRFs??
  
  I want to make an information extraction application using CRF Named Entity Recognition (NER).
  
  I got some tutorial for that: <https://eli5.readthedocs.io/en/latest/tutorials/sklearn_crfsuite.html#training-data>
  
  **But** I don't know the proses each step, like training proses, evaluation, and testing
  
  I use this code :
  
  ```
    data_frame = eli5.format_as_dataframes(
              eli5.explain_weights_sklearn_crfsuite(self.crf))
  
  ```
  
  **Targets**
  [![enter image description here](https://i.sstatic.net/bCHpg.png)](https://i.sstatic.net/bCHpg.png)
  
  **Transition Features**
  [![enter image description here](https://i.sstatic.net/jqlGi.png)](https://i.sstatic.net/jqlGi.png)
  
  How to get that number ?
  
  and 1 more thing makes me confused:
  
  ```
  crf = sklearn_crfsuite.CRF(
      algorithm='lbfgs',
      c1=0.1,
      c2=0.1,
      max_iterations=20,
      all_possible_transitions=False,
  )
  
  ```
  
  What is the algorithm `lbfgs`? Is the CRF not an algorithm? Why do I need `lbfgs`? What is exactly a conditional random field?
  
  **Tags:** machine-learning, natural-language-processing, definitions, probabilistic-graphical-models, conditional-random-field
  
  > **Comments:**
  > **username_1**: I will provide an answer later, but you will have to wait (unless someone provides an answer meanwhile). Anyway, it is ok to be confused when it comes to CRFs, especially if you don't have a solid mathematical background.  
  > **username_0**: okay, thank you for responding I really appreciate that @username_1  
  > **username_0**: heyy i still waiting your answer @username_1 :(  
  > **username_1**: Hey! Sorry for having made you wait for a long time without warning you. CRFs involve a lot of concepts. So, a satisfactory will possibly be quite long, which would have required some time. Meanwhile, I couldn't have spent so much time to give this answer. I will try to give you an answer this weekend.  
  > **username_0**: @username_1 Ok, i will waiting your answer :(  
  > **username_0**: @username_1 hey :( i am still waiting  
  
  ---
  
  ## 0 answers
  
  