Home/ Questions/Q 6786299
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-26T17:13:44+00:00

I am struggling at the moment with Mallet’s ridiculously poor documentation regarding HMMs. I

  • 0

I am struggling at the moment with Mallet’s ridiculously poor documentation regarding HMMs. I have managed to import the data into instances(adapted from the ImportExample.java snippet) and I was just wondering how they can be used to train an HMM model.
I first started by creating an HMM instance but I wasn’t sure whether to go for:

    HMM hmm = new HMM(instances.getDataAlphabet(), instances.getTargetAlphabet());

Or use the same data alphabet twice like so:

    HMM hmm = new HMM(instances.getDataAlphabet(), instances.getDataAlphabet());

Either way when I get to 

    hmm.train(instances);

I get the following error:

cc.mallet.types.FeatureVector cannot be cast to
cc.mallet.types.FeatureVectorSequence

I would be grateful for any help you can provide.

Cheers

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    I have managed to solve this particular problem and thought it may be useful to others with the same problem. There is a solution within the examples package in mallet: http://hg-iesl.cs.umass.edu/hg/mallet/file/83adf71b0824/src/cc/mallet/examples/TrainHMM.java

    The main problem was related to how you imported the data through the pipe. Also from what I can tell it helps if you data is in this format:

    TOKEN  TAG 
TOKEN  TAG

    I assuming you can have features in between the TOKEN and TAG but am not a 100% sure. If anyone knows of any good examples and documentation about using HMM within mallet, please let me know.

    • 0