data_preprocessor.py

import numpy as np

def read_rating(path, num_users, num_items,num_total_ratings, a, b, train_ratio):
    fp = open(path + "ratings.dat")

    user_train_set = set()
    user_test_set = set()
    item_train_set = set()
    item_test_set = set()

    R = np.zeros((num_users,num_items))
    mask_R = np.zeros((num_users, num_items))
    C = np.ones((num_users, num_items)) * b

    train_R = np.zeros((num_users, num_items))
    test_R = np.zeros((num_users, num_items))

    train_mask_R = np.zeros((num_users, num_items))
    test_mask_R = np.zeros((num_users, num_items))

    random_perm_idx = np.random.permutation(num_total_ratings)
    train_idx = random_perm_idx[0:int(num_total_ratings*train_ratio)]
    test_idx = random_perm_idx[int(num_total_ratings*train_ratio):]

    num_train_ratings = len(train_idx)
    num_test_ratings = len(test_idx)

    lines = fp.readlines()
    for line in lines:
        user,item,rating,_ = line.split("::")
        user_idx = int(user) - 1
        item_idx = int(item) - 1
        R[user_idx,item_idx] = int(rating)
        mask_R[user_idx,item_idx] = 1
        C[user_idx,item_idx] = a

    ''' Train '''
    for itr in train_idx:
        line = lines[itr]
        user,item,rating,_ = line.split("::")
        user_idx = int(user) - 1
        item_idx = int(item) - 1
        train_R[user_idx,item_idx] = int(rating)
        train_mask_R[user_idx,item_idx] = 1

        user_train_set.add(user_idx)
        item_train_set.add(item_idx)

    ''' Test '''
    for itr in test_idx:
        line = lines[itr]
        user, item, rating, _ = line.split("::")
        user_idx = int(user) - 1
        item_idx = int(item) - 1
        test_R[user_idx, item_idx] = int(rating)
        test_mask_R[user_idx, item_idx] = 1

        user_test_set.add(user_idx)
        item_test_set.add(item_idx)

    return R, mask_R, C, train_R, train_mask_R, test_R, test_mask_R,num_train_ratings,num_test_ratings,\
user_train_set,item_train_set,user_test_set,item_test_set