What does "ERROR: fstsymbols: Saving osymbols but there are no output symbols" means and how can i solve it?

Question

I wanted to update the language model of Kaldi model used in Vosk. I was following the Updating the language model in Vosk Adaptation

I had this ERROR: fstsymbols: Saving osymbols but there are no output symbols when I try to run fstsymbols --save_osymbols=words.txt Gr.fst > /dev/null . I guess the words.txt is the new text which I want to recognize right?

Answer 1

What this command does is it saves all the output symbol table of the current finite state transducer (language model @ .fst file) into a text file called words.txt.

$ fstsymbols --help
...
  --save_osymbols: type = string, default = ""
  Save fst file's output symbol table to file
...

This file would be used in the next command, where text.txt is a file containing your custom list of words.

farcompilestrings --fst_type=compact --symbols=words.txt --keep_symbols text.txt | \
 ngramcount | ngrammake | \
 fstconvert --fst_type=ngram > Gr.new.fst