train_chatbot.py

import nltk
nltk.download('punkt')
nltk.download('wordnet')
from nltk.stem import WordNetLemmatizer

import json
import pickle

import numpy as np
from tensorflow.keras import Sequential
from tensorflow.keras.layers import Conv2D, Flatten, Dense, Dropout
from tensorflow.keras.optimizers import SGD

lemmatizer = WordNetLemmatizer()
words = []
classes = []
documents = []
ignore_words = ['?', '!']
data_file = open('intents.json').read()
intents = json.loads(data_file)
print(intents)

# intents: gruppi di conversazioni-tipo
# patterns: possibili interazioni dell'utente
for intent in intents['intents']:
    for pattern in intent['patterns']:

        # tokenizzo ogni parola
        w = nltk.word_tokenize(pattern)
        words.extend(w)
        # aggiungo all'array documents
        documents.append((w, intent['tag']))

        # adding classes to our class list
        if intent['tag'] not in classes:
            classes.append(intent['tag'])

words = [lemmatizer.lemmatize(w.lower()) for w in words if w not in ignore_words]

pickle.dump(words, open('words.pkl','wb'))
pickle.dump(classes, open('classes.pkl','wb'))

# preparazione per l'addestramento della rete
training = []
output_empty = [0] * len(classes)
for doc in documents:
    # bag of words
    bag = []
    # lista di tokens
    pattern_words = doc[0]
    # lemmatizzazione dei token
    pattern_words = [lemmatizer.lemmatize(word.lower()) for word in pattern_words]
    # se la parola matcha, inserisco 1, altriment 0
    for w in words:
        bag.append(1) if w in pattern_words else bag.append(0)

    output_row = list(output_empty)
    output_row[classes.index(doc[1])] = 1

    training.append([bag, output_row])

training = np.array(training)
# creazione dei set di train e di test: X - patterns, Y - intents
train_x = list(training[:,0])
train_y = list(training[:,1])

# creazione del modello
model = Sequential()
model.add(Dense(128, input_shape=(len(train_x[0]),), activation='relu'))
model.add(Dropout(0.5))
model.add(Dense(64, activation='relu'))
model.add(Dropout(0.5))
model.add(Dense(len(train_y[0]), activation='softmax'))

sgd = SGD(lr=0.01, decay=1e-6, momentum=0.9, nesterov=True)
model.compile(loss='categorical_crossentropy', optimizer=sgd, metrics=['accuracy'])

#fitting and saving the model
hist = model.fit(np.array(train_x), np.array(train_y), epochs=300, batch_size=5, verbose=1)
model.save('chatbot_model.h5', hist)

print("Modello creato!")