def get_mentioned_landmarks(thesaurus, str_instruction):
split_instr = split_instruction(clean_instruction(str_instruction))
word2term = thesaurus["word2term"]
term_groundings = thesaurus["term_groundings"]
lm_name2index = get_landmark_name_to_index()
# Map each word in the instruction to it's corresponding term:
split_instr_terms = words_to_terms(split_instr, word2term)
mentioned_landmark_names = set()
# For each term, find all the landmarks that have been mentioned
for term in split_instr_terms:
for landmark_name in term_groundings[term]["landmarks"]:
mentioned_landmark_names.add(landmark_name)
mentioned_landmark_names = list(mentioned_landmark_names)
mentioned_landmark_indices = [
lm_name2index[name] for name in mentioned_landmark_names
]
return mentioned_landmark_names, mentioned_landmark_indices
def cluster_corpus(corpus, train_instructions, max_edit_distance=3):
english = load_english_vocabulary()
terms = {}
potential_misspellings = []
# Count the number of times each word occurs in the corpus
word_counts = {}
for word in corpus:
word_counts[word] = 0
for env_id, instruction_sets in train_instructions.items():
for instruction_set in instruction_sets[0]["instructions"]:
instruction_str = instruction_set["instruction"]
instr_split = split_instruction(clean_instruction(instruction_str))
for word in instr_split:
word_counts[word] += 1
for word in corpus:
if word in english:
terms[word] = [word]
else:
potential_misspellings.append(word)
terms[UNK_TERM] = []
# Find the closest english word by edit distance
edit_dists = np.zeros((len(terms)))
term_list = sorted(list(terms.keys()))
unresolved_words = []
for i, misspelled_word in enumerate(potential_misspellings):
# Words that contain a numbers should be assumed not to be misspellings
if any(char.isdigit() for char in misspelled_word):
unresolved_words.append(misspelled_word)
continue
# For other words, see if they might be misspellings of one of the terms
for j, term in enumerate(term_list):
edit_dists[j] = levenshtein(misspelled_word, term)
closest = int(np.argmin(edit_dists))
min_dist = edit_dists[closest]
# If the misspelled word is likely a misspelling of the closest term, add it in, except to the "NA" term
if min_dist <= max_edit_distance and term_list[closest] != UNK_TERM:
terms[term_list[closest]].append(misspelled_word)
# Otherwise add it to the list of unresolved words that are too different from every term
else:
unresolved_words.append(misspelled_word)
rejected_words = []
# Handle words that are not misspellings
for unresolved_word in unresolved_words:
# If the word is not a misspelling and is also very infrequent, reject it
if word_counts[unresolved_word] < MIN_TERM_OCCURENCES:
rejected_words.append(unresolved_word)
# Otherwise create a term for this word
else:
terms[unresolved_word] = [unresolved_word]
# For each rejected word, add it to the unknown term
for rejected_word in rejected_words:
terms[UNK_TERM].append(rejected_word)
print("After clustering words, found " + str(len(rejected_words)) +
" rare ones that have been rejected:")
print(rejected_words)
print("...")
return terms, rejected_words
def ground_terms(word2id, clustered_corpus, landmark_names,
train_instructions):
# the clustered corpus is a dictionary of lists, where the keys are valid english words and the values are
# lists of words found in the corpus that are assumed to be misspellings of the key valid words
# We make the distinction that a word is any word in an instruction
# Terms are words in the english vocabulary. Multiple words (misspellings) can map to a single term.
num_terms = len(clustered_corpus)
vocab_size = len(word2id)
num_landmarks = len(landmark_names)
# This is gonna be the new word2id, once we start using the thesaurus
term2id = {}
id2term = {}
for i, term in enumerate(sorted(clustered_corpus.keys())):
term2id[term] = i
id2term[i] = term
# Calculate the mutual information between each cluster and each landmark
# Number of times each term appears in an instruction
term_occurences = np.zeros(num_terms)
# Number of times each landmark appears near a segment path
landmark_occurences = np.zeros(num_landmarks)
# The number of times each term and landmark combination appears in the instruction and near the path
term_landmark_cooccurences = np.zeros((num_terms, num_landmarks))
# The number of total segments that were considered
total_occurences = 0
landmark_indices = get_landmark_name_to_index()
# Inverse the clusters so that we can efficiently map each word in each instruction to it's cluster core
word2term = {}
for real_word, misspellings in clustered_corpus.items():
for misspelling in misspellings:
word2term[misspelling] = real_word
# Count landmark and word occurences and co-occurences
for env_id, instruction_sets in train_instructions.items():
path = load_path(env_id)
env_config = load_env_config(env_id)
for instruction_set in instruction_sets[0]["instructions"]:
instruction_str = instruction_set["instruction"]
start_idx = instruction_set["start_idx"]
end_idx = instruction_set["end_idx"]
present_landmarks = close_landmark_names(env_config, path,
start_idx, end_idx)
present_lm_indices = [
landmark_indices[lm] for lm in present_landmarks
]
mentioned_words = split_instruction(
clean_instruction(instruction_str))
mentioned_terms = words_to_terms(mentioned_words, word2term)
for term in mentioned_terms:
term_id = term2id[term]
term_occurences[term_id] += 1
for lm_idx in present_lm_indices:
landmark_occurences[lm_idx] += 1
for term in mentioned_terms:
term_id = term2id[term]
term_landmark_cooccurences[term_id][lm_idx] += 1
total_occurences += 1
term_prob = np.expand_dims(term_occurences / total_occurences,
1).repeat(num_landmarks, 1)
landmark_prob = np.expand_dims(landmark_occurences / total_occurences,
0).repeat(num_terms, 0)
term_and_landmark_prob = term_landmark_cooccurences / total_occurences
# term_and_landmark_prob has dimensions 0: terms, 1: landmarks
mutual_info_factor = term_and_landmark_prob / (landmark_prob * term_prob +
1e-27)
#mutual_info_factor = term_and_landmark_prob / ((1 / num_landmarks) * term_prob + 1e-9)
mutual_info = term_and_landmark_prob * np.log(mutual_info_factor + 1e-27)
# The above line is the correct formula for mutual information. For our case, below formula might be better?
# The mutual information is higher for common words than uncommon ones. We might prefer the opposite effect.
# On the other hand, uncommon words are more likely to spuriously correlate with landmarks, which will cause a
# less reliable corpus.
#mutual_info = np.log(mutual_info_factor + 1e-27)
# Ground each term and produce the thesaurus
term_meanings = {}
common_words = []
for i in range(num_terms):
grounded_lm_indices = [
idx for idx in range(num_landmarks)
if mutual_info[i][idx] > MUTUAL_INFO_THRESHOLD
]
grounded_lm_names = [
landmark_names[idx] for idx in grounded_lm_indices
]
mutual_infos = np.asarray(
[mutual_info[i][idx] for idx in grounded_lm_indices])
args = list(np.argsort(mutual_infos))
grounded_lm_names = list(
reversed([grounded_lm_names[idx] for idx in args]))
mutual_infos = list(reversed([mutual_infos[idx] for idx in args]))
# If the word is too common to be referring to a landmark, ignore ita
this_term_prob = term_prob[i][0]
if this_term_prob > MAX_TERM_PROB:
common_words.append(id2term[i])
grounded_lm_names = []
mutual_infos = []
term_meanings[id2term[i]] = \
{
"landmarks": grounded_lm_names,
"mutual_info": mutual_infos,
"term_prob": this_term_prob
}
for k in term_meanings.keys():
if len(term_meanings[k]["landmarks"]) > 0:
print(k, term_meanings[k])
print("Ignored groundings for these common words: " + str(common_words))
return term_meanings, word2term