{"action":"opened","issue":{"url":"https://api.github.com/repos/jmschrei/pomegranate/issues/6","labels_url":"https://api.github.com/repos/jmschrei/pomegranate/issues/6/labels{/name}","comments_url":"https://api.github.com/repos/jmschrei/pomegranate/issues/6/comments","events_url":"https://api.github.com/repos/jmschrei/pomegranate/issues/6/events","html_url":"https://github.com/jmschrei/pomegranate/issues/6","id":72973553,"number":6,"title":"Exception in _train_once_baum_welch with MultivariateGaussianDistribution","user":{"login":"matthiasplappert","id":124243,"avatar_url":"https://avatars.githubusercontent.com/u/124243?v=3","gravatar_id":"","url":"https://api.github.com/users/matthiasplappert","html_url":"https://github.com/matthiasplappert","followers_url":"https://api.github.com/users/matthiasplappert/followers","following_url":"https://api.github.com/users/matthiasplappert/following{/other_user}","gists_url":"https://api.github.com/users/matthiasplappert/gists{/gist_id}","starred_url":"https://api.github.com/users/matthiasplappert/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/matthiasplappert/subscriptions","organizations_url":"https://api.github.com/users/matthiasplappert/orgs","repos_url":"https://api.github.com/users/matthiasplappert/repos","events_url":"https://api.github.com/users/matthiasplappert/events{/privacy}","received_events_url":"https://api.github.com/users/matthiasplappert/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-05-04T09:38:21Z","updated_at":"2015-05-04T09:38:21Z","closed_at":null,"body":"I'm having a problem when using `MultivariateGaussianDistribution` in a HMM. My HMM has 10 states and is used with sequences that have 43 features. My covariance matrix is therefore 43x43 and diagonal. I do pass in the `diagonal=True` flag when training, but the described problem also occurs if it is set to `False`. When training with Baum-Welch, the library will log with the following exception:\r\n\r\n```\r\nException TypeError: \"object of type 'NoneType' has no len()\" in 'pomegranate.hmm.HiddenMarkovModel._train_once_baum_welch' ignored\r\n```\r\n\r\nThis happens in the first round and the training improvement will then be 0.0. Naturally, the algorithm will then terminate since the threshold is reached.\r\n\r\nI've tried to figure out exactly what is going on, but I don't have a lot of experience with Cython and wasn't able to figure out where the exception is raised.\r\n\r\nIt would be great if someone has ideas what could cause this. If someone has pointers on how to find the source of the exception I'm more than glad to do some debugging myself, too."}}