def generate_symbol_tables(lexicon, n=3):
'''
Return word, phone and state symbol tables based on the supplied lexicon
Args:
lexicon (dict): lexicon to use, created from the parse_lexicon() function
n (int): number of states for each phone HMM
Returns:
word_table (fst.SymbolTable): table of words
phone_table (fst.SymbolTable): table of phones
state_table (fst.SymbolTable): table of HMM phone-state IDs
'''
state_table = fst.SymbolTable()
phone_table = fst.SymbolTable()
word_table = fst.SymbolTable()
state_table.add_symbol('<eps>')
phone_table.add_symbol('<eps>')
word_table.add_symbol('<eps>')
for word, phones in lexicon.items():
word_table.add_symbol(word)
for phone in phones:
phone_table.add_symbol(phone)
for i in range(1, n+1):
state_table.add_symbol('{}_{}'.format(phone,i))
return word_table, phone_table, state_table
def generate_output_table(word_table, phone_table):
output_table = fst.SymbolTable()
for phone_id, phone_str in list(phone_table):
output_table.add_symbol(phone_str)
for word_id, word_str in list(word_table):
output_table.add_symbol(word_str)
return output_table
def generate_symbols_table(lexicon, n=3):
'''
Return word, phone and state symbol tables based on the supplied lexicon
Args:
lexicon (dict): lexicon to use, created from the parse_lexicon() function
n (int): number of states for each phone HMM
Returns:
word_table (fst.SymbolTable): table of words
phone_table (fst.SymbolTable): table of phones
state_table (fst.SymbolTable): table of HMM phone-state IDs
'''
state_table = fst.SymbolTable()
phone_table = fst.SymbolTable()
word_table = fst.SymbolTable()
# add empty <eps> symbol to all tables
state_table.add_symbol('<eps>')
phone_table.add_symbol('<eps>')
word_table.add_symbol('<eps>')
for word, phone_list in lexicon.items():
word_table.add_symbol(word)
for phones in phone_list: # for each phone
for p in phones:
# print(f"Adding phone {p} from word {word} to phone table")
phone_table.add_symbol(p)
for i in range(1, n + 1): # for each state 1 to n
state_table.add_symbol('{}_{}'.format(p, i))
# <!> DEBUGS
# for word in word_table:
# print(word)
# print('word_table: {}\nphone_table: {}\nstate_table: {}'.format(list(word_table), list(phone_table), list(state_table)))
return word_table, phone_table, state_table
# We start by importing the OpenFst Python wrapper:
# In[1]:
import openfst_python as fst
import math
partner = "s1922482" # Minghui Zhao
# Then we create tables for our symbols
# In[2]:
input_sym = fst.SymbolTable()
output_sym = fst.SymbolTable()
input_sym.add_symbol('<eps>') # by convention, <eps> always
# has symbol zero
input_sym.add_symbol('a') # input symbols
input_sym.add_symbol('b')
output_sym.add_symbol('<eps>') # output symbols
output_sym.add_symbol('d')
output_sym.add_symbol('c')
# A **SymbolTable()** is simply a table associating symbols and indexes. We add symbols to the table with the method **add_symbol()**
#
# Now that we've got our symbol tables, we will build the FST itself:
#================================================
# List of symbols
# You need to modify the list below to match
# the symbols you need. My advice would be:
# (1) Draw the lattice on a piece of paper,
# (2) Make a list of the transitions, and
# (3) As you go through the transitions,
# include your symbolss in the symbol
# list.
#
# Notice that the first symbol is the
# "epsilon", for when you expect empty strings.
#================================================
fstSymbols = fst.SymbolTable()
fstSymbols.add_symbol("<eps>", 0)
fstSymbols.add_symbol("c", 1)
fstSymbols.add_symbol("a", 2)
fstSymbols.add_symbol("t", 3)
fstSymbols.add_symbol("s", 4)
fstSymbols.add_symbol("-PL", 5)
fstSymbols.add_symbol("i", 6)
fstSymbols.add_symbol("e", 7)
fstSymbols.add_symbol("y-PL", 8)
fstSymbols.add_symbol("d", 9)
fstSymbols.add_symbol("o", 10)
fstSymbols.add_symbol("g", 11)
fstSymbols.add_symbol("y", 12)
fstSymbols.add_symbol("u", 13)
fstSymbols.add_symbol("-s", 14)