In Math, according to the wiki, vector space is a collection of objects called vectors, which may be added together and multiplied(scaled) together. the objects can be of different kind such as height, blood pressure, weight etc. Matrices are a useful notion to encode linear maps, written as a rectangular array of scalars, for example … Continue reading Vector and Tensor

Logistic regression is different from linear regression in the sense that the outcome is discrete values rather than continuous number. Using the prediction of diabetics as an example, there are three measurements - weight, height, blood pressure one may have, and will use these three values to predict if the object is diabetic or not … Continue reading Logistic Regression

Loss function, in essence is to measure how badly the machine learning algorithm screwed up the prediction quantitatively. Definition from Stanford open course is To have a concrete feeling, the below example from this blog post is more straightforward. There are multiple ways to measure the loss, mean squared error (MSE), likelihood loss, log loss(cross … Continue reading Loss Function

It's easier to start from understanding what "gradient" means here. According to Lex Fridman at MIT, “A gradient measures how much the output of a function changes if you change the inputs a little bit.” . Gradient descent can be thought of climbing down to the bottom of a valley. Picture if we have the valley … Continue reading Gradient Descent

Heroku is extensively used because of it's power to facilitate a quick app launch, to be more official, it " runs and manages applications written in Ruby, Node.js, Java, Python, Clojure, Scala, Go and PHP", Google App Engine is also providing similar service, while Heroku, now a subsidiary of Salesforce is edging out. Following the … Continue reading Use Heroku To Deploy An App

This is truly mind-blowing to watch a genius in motion - running through of how to build up an AI start-up in 40 minutes. In this video, he breaks down to 10 steps to build a complete start-up like this. Step 1 List Personal ProblemsStep 2 Market Research (competing products)Step 3 Buy DomainStep 4 Create Landing PageStep 5 Share Landing … Continue reading Watch Saraj Raval To Build A Start-up

Regular Expression in programming is quite daunting but also very important to learn. It's like a separate min-language to grasp with lot of patience and attention to nuances. First off, what is "Regular Expressions"? According to Wikipedia, "In computing, regular expressions provide a concise and flexible means for identifying strings of text of interest, such … Continue reading Regular Expressions

What's the Decorator in Python? Decorators are functions which modify the functionality of other functions. It's greatly useful in Python programming. To illustrate, see the codes def a_decorator(func): def wrapper(): print('We can do sth. before a func is called...') func() print('... and we can do sth. after it is called...') return wrapper() def a_func(): print("Hi, … Continue reading Decorator In Python

The key topics are: pointer, reference, virtual method and polymorphism. What is a pointer? It contains the address of variable in the computer's internal memory - RAM; it itself is represented by a variable in bytes looking like 0x7fff6472e92c. There are two signs to know in depth to fully understand how to use pointer and … Continue reading C++ Core Knowledge To Get The Ability To Read (Continued)

The key points are beautifully addressed in Derek Banas's one hour video. These concepts are gone through: ternary operator; file i/o; pointers; reference operator; class/objects; private; static variables; public/encapsulation; constructors; static functions; this; inheritance; call superclass constructor; execute static method; virtual methods; polymorphism; abstract data type. Commonly seen signs << after cout is just a … Continue reading C++ Core Knowledge To Get The Ability To Read