I am trying to replace the dot product for loop using something faster like NumPy
I did research on dot product and kind of understand and can get it working with toy data in a few ways in but not 100% when it comes to implementing it for actual use with a data frame.
I looked at these and other SO threads to no luck avoide loop dot product, matlab and dot product subarrays without for loop and multiple numpy dot products without a loop
looking to do something like this which works with toy numbers in np array
u1 =np.array([1,2,3])
u2 =np.array([2,3,4])
v1.dot(v2)
20
u1 =np.array([1,2,3])
u2 =np.array([2,3,4])
(u1 * u2).sum()
20
u1 =np.array([1,2,3])
u2 =np.array([2,3,4])
sum([x1*x2 for x1, x2 in zip (u1, u2)])
20
this is the current working get dot product
I would like to do this with out the for loop
def get_dot_product(self, courseid1, courseid2, unit_vectors):
u1 = unit_vectors[courseid1]
u2 = unit_vectors[courseid2]
dot_product = 0.0
for dimension in u1:
if dimension in u2:
dot_product += u1[dimension] * u2[dimension]
return dot_product
** code**
#!/usr/bin/env python
# coding: utf-8
class SearchRecommendationSystem:
def __init__(self):
pass
def get_bag_of_words(self, titles_lines):
bag_of_words = {}
for index, row in titles_lines.iterrows():
courseid, course_bag_of_words = self.get_course_bag_of_words(row)
for word in course_bag_of_words:
word = str(word).strip() # added
if word not in bag_of_words:
bag_of_words[word] = course_bag_of_words[word]
else:
bag_of_words[word] += course_bag_of_words[word]
return bag_of_words
def get_course_bag_of_words(self, line):
course_bag_of_words = {}
courseid = line['courseid']
title = line['title'].lower()
description = line['description'].lower()
wordlist = title.split() + description.split()
if len(wordlist) >= 10:
for word in wordlist:
word = str(word).strip() # added
if word not in course_bag_of_words:
course_bag_of_words[word] = 1
else:
course_bag_of_words[word] += 1
return courseid, course_bag_of_words
def get_sorted_results(self, d):
kv_list = d.items()
vk_list = []
for kv in kv_list:
k, v = kv
vk = v, k
vk_list.append(vk)
vk_list.sort()
vk_list.reverse()
k_list = []
for vk in vk_list[:10]:
v, k = vk
k_list.append(k)
return k_list
def get_keywords(self, titles_lines, bag_of_words):
n = sum(bag_of_words.values())
keywords = {}
for index, row in titles_lines.iterrows():
courseid, course_bag_of_words = self.get_course_bag_of_words(row)
term_importance = {}
for word in course_bag_of_words:
word = str(word).strip() # extra
tf_course = (float(course_bag_of_words[word]) / sum(course_bag_of_words.values()))
tf_overall = float(bag_of_words[word]) / n
term_importance[word] = tf_course / tf_overall
keywords[str(courseid)] = self.get_sorted_results(term_importance)
return keywords
def get_inverted_index(self, keywords):
inverted_index = {}
for courseid in keywords:
for keyword in keywords[courseid]:
if keyword not in inverted_index:
keyword = str(keyword).strip() # added
inverted_index[keyword] = []
inverted_index[keyword].append(courseid)
return inverted_index
def get_search_results(self, query_terms, keywords, inverted_index):
search_results = {}
for term in query_terms:
term = str(term).strip()
if term in inverted_index:
for courseid in inverted_index[term]:
if courseid not in search_results:
search_results[courseid] = 0.0
search_results[courseid] += (
1 / float(keywords[courseid].index(term) + 1) *
1 / float(query_terms.index(term) + 1)
)
sorted_results = self.get_sorted_results(search_results)
return sorted_results
def get_titles(self, titles_lines):
titles = {}
for index, row in titles_lines.iterrows():
titles[row['courseid']] = row['title'][:60]
return titles
def get_unit_vectors(self, keywords, categories_lines):
norm = 1.884
cat = {}
subcat = {}
for line in categories_lines[1:]:
courseid_, category, subcategory = line.split('\t')
cat[courseid_] = category.strip()
subcat[courseid_] = subcategory.strip()
unit_vectors = {}
for courseid in keywords:
u = {}
if courseid in cat:
u[cat[courseid]] = 1 / norm
u[subcat[courseid]] = 1 / norm
for keyword in keywords[courseid]:
u[keyword] = (1 / float(keywords[courseid].index(keyword) + 1) / norm)
unit_vectors[courseid] = u
return unit_vectors
def get_dot_product(self, courseid1, courseid2, unit_vectors):
u1 = unit_vectors[courseid1]
u2 = unit_vectors[courseid2]
dot_product = 0.0
for dimension in u1:
if dimension in u2:
dot_product += u1[dimension] * u2[dimension]
return dot_product
def get_recommendation_results(self, seed_courseid, keywords, inverted_index, unit_vectors):
courseids = []
seed_courseid = str(seed_courseid).strip()
for keyword in keywords[seed_courseid]:
for courseid in inverted_index[keyword]:
if courseid not in courseids and courseid != seed_courseid:
courseids.append(courseid)
dot_products = {}
for courseid in courseids:
dot_products[courseid] = self.get_dot_product(seed_courseid, courseid, unit_vectors)
sorted_results = self.get_sorted_results(dot_products)
return sorted_results
def Final(self):
print("Reading Title file.......")
titles_lines = open('s2-titles.txt', encoding="utf8").readlines()
print("Reading Category file.......")
categories_lines = open('s2-categories.tsv', encoding = "utf8").readlines()
print("Getting Supported Functions Data")
bag_of_words = self.get_bag_of_words(titles_lines)
keywords = self.get_keywords(titles_lines, bag_of_words)
inverted_index = self.get_inverted_index(keywords)
titles = self.get_titles(titles_lines)
print("Getting Unit Vectors")
unit_vectors = self.get_unit_vectors(keywords=keywords, categories_lines=categories_lines)
#Search Part
print("\n ############# Started Search Query System ############# \n")
query = input('Input your search query: ')
while query != '':
query_terms = query.split()
search_sorted_results = self.get_search_results(query_terms, keywords, inverted_index)
print(f"==> search results for query: {query.split()}")
for search_result in search_sorted_results:
print(f"{search_result.strip()} - {str(titles[search_result]).strip()}")
#ask again for query or quit the while loop if no query is given
query = input('Input your search query [hit return to finish]: ')
print("\n ############# Started Recommendation Algorithm System ############# \n")
# Recommendation ALgorithm Part
seed_courseid = (input('Input your seed courseid: '))
while seed_courseid != '':
seed_courseid = str(seed_courseid).strip()
recom_sorted_results = self.get_recommendation_results(seed_courseid, keywords, inverted_index, unit_vectors)
print('==> recommendation results:')
for rec_result in recom_sorted_results:
print(f"{rec_result.strip()} - {str(titles[rec_result]).strip()}")
get_dot_product_ = self.get_dot_product(seed_courseid, str(rec_result).strip(), unit_vectors)
print(f"Dot Product Value: {get_dot_product_}")
seed_courseid = (input('Input seed courseid [hit return to finish]:'))
if __name__ == '__main__':
obj = SearchRecommendationSystem()
obj.Final()
s2-categories.tsv
courseid category subcategory
21526 Design 3D & Animation
153082 Marketing Advertising
225436 Marketing Affiliate Marketing
19482 Office Productivity Apple
33883 Office Productivity Apple
59526 IT & Software Operating Systems
29219 Personal Development Career Development
35057 Personal Development Career Development
40751 Personal Development Career Development
65210 Personal Development Career Development
234414 Personal Development Career Development
Example of how s2-titles.txt looks
courseidXXXYYYZZZtitleXXXYYYZZZdescription
3586XXXYYYZZZLearning Tools for Mrs B's Science Classes This is a series of lessons that will introduce students to the learning tools that will be utilized throughout the schoXXXYYYZZZThis is a series of lessons that will introduce students to the learning tools that will be utilized throughout the school year The use of these tools serves multiple purposes 1 Allow the teacher to give immediate and meaningful feedback on work that is in progress 2 Allow students to have access to content and materials when outside the classroom 3 Provide a variety of methods for students to experience learning materials 4 Provide a variety of methods for students to demonstrate learning 5 Allow for more time sensitive correction grading and reflections on concepts that are assessed
Evidently unit_vectors is a dictionary, from which you extract to 2 values, u1 and u2.
But what are those? Evidently dicts as well (this iteration would not make sense with a list):
for dimension in u1:
if dimension in u2:
dot_product += u1[dimension] * u2[dimension]
But what is u1[dimension]? A list? An array.
Normally dict are access by key as you do here. There isn't a numpy style "vectorization". vals = list(u1.values()) gets a lists of all values, and conceivably that could be made into an array (if the elements are right)
arr1 = np.array(list(u1.values()))
and a np.dot(arr1, arr2) might work
You'll get the best answers if you give small concrete examples - with real working data (and skip the complex generating code). Focus on the core of the problem, so we can grasp the issue with a 30 second read!
===
Looking more in depth at your dot function; this replicates the core (I think). Initially I missed the fact that you aren't iterating on u2 keys, but rather seeking matching ones.
def foo(dd):
x = 0
u1 = dd['u1']
u2 = dd['u2']
for k in u1:
if k in u2:
x += u1[k]*u2[k]
return x
Then making a dictionary of dictionaries:
In [30]: keys=list('abcde'); values=[1,2,3,4,5]
In [31]: adict = {k:v for k,v in zip(keys,values)}
In [32]: dd = {'u1':adict, 'u2':adict}
In [41]: dd
Out[41]:
{'u1': {'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5},
'u2': {'a': 1, 'b': 2, 'c': 3, 'd': 4, 'e': 5}}
In [42]: foo(dd)
Out[42]: 55
In this case the subdictionaries match, so we get the same value with a simple array dot:
In [43]: np.dot(values,values)
Out[43]: 55
But if u2 was different, with different key/value pairs, and possibly different keys the result will be different. I don't see a way around the iterative access by keys. The sum-of-products part of the job is minor compared to the dictionary access.
In [44]: dd['u2'] = {'e':3, 'f':4, 'a':3}
In [45]: foo(dd)
Out[45]: 18
We could construct other data structures that are more suitable to a fast dot like calculation. But that's another topic.