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Blog Posts

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Algorithm Optimization With Dynamic Programming

May 17th, 2019

Dynamic programming (DP), is an algorithm design technique used to turn exponential complexity problems into polynomial complexity problems. Described as careful brute force (Erik Demaine - MIT course 6.006), problems are deconstructed into overlaping subproblems, solved indepedently with brute force, subproblems solutions are then cached and reused. The reusability aspect being a major contributor to the optimization due to the overlapping nature of the subproblems.

Mathematics

Nginx Proxy Pass

May 10th, 2019

In a previous post, we saw how we could host an ASP.NET Core application behind Nginx. We saw that Kestrel works as a selfhost webserver and that in order to get request forwarded to it, we need to proxy them using the location and proxy_pass directives. Today we will look into some details regarding path handling, ensuring that our requests are forwarded properly.

NGINX

Nginx Gzip

May 3rd, 2019

When building single page applications, like Angular applications, where the entire application is sent over HTTP, compressing static files before serving them can provide a major boost in performance, drastically reducing latency. One of the most common compression algorithm widely supported by reverse proxies and browsers is Gzip. Today we will see how we can enable gzip compression on Nginx.

NGINX

Angular Webpack Proxy Dev Server

Apr 26th, 2019
Proxy Calls

Angular CLI provides an easy way to host Angular applications during development by using Webpack dev server. Due to the fact that Webpack dev server is a web server, our frontend gets hosted on a separate web server which causes CORS issues if we want to call endpoints on a backend which we also host locally for development. Today we will see how we can use one of the features of Webpack dev server to setup a proxy during development which will proxy calls from the Angular application to our local backend hence by passing the CORS issue.

Angular

Delayed Evaluation And Infinite Stream

Apr 19th, 2019

In our previous post on mutability, we discussed the fact that time was to be taken into consideration when mutability was involved. We observed objects lifetime as instant by instant, computing and assigning objects states for each instant. Another way to look at time is to consider the state as a discrete set of values. From this perspective, we can see the time as being an infinite sequence, a stream, and the state can also be seen as a stream computed out of time.

Racket

Powershell

Apr 12th, 2019

PowerShell is versatile command line shell which comes with a powerful scripting language. It is now even more available than before with the new PowerShell Core which makes it available on Linux. Even though the main commands in the scripting language have been around for ages, I always see myself having to re-learn how to use it every time I need to write a script.

Azure

The Cost And Benefit Of Mutability

Apr 5th, 2019

Mutability is a topic of high interest in the view of developers adventuring themselves in functional programming languages where it is generally unwelcomed and, in some instances, made voluntarily hard to implement. In contrast, object oriented programming has assignment at its core. Objects are represented as entity with a state modifiable over the lifetime of the application.

Racket

Understand Data Abstraction With Examples

Mar 29th, 2019

Data abstraction allows us to think about complex systems in term of their properties rather than their implementations. Reasoning in term of properties provides a ground of assumptions which can be used to create new systems. In common programming languages, abstraction is present everywhere, as interfaces, as abstract and regular classes, as functions, as function signatures, as user interfaces, etc. All of theses tools provide a way to build layers of abstraction which we can work on top of to create new functionalities by manipulating data on the appropriate layer.

Racket

Angular Progressive Web App

Mar 22nd, 2019
Angular Progressive Web App manifest.json file

Progressive Web App allows an Angular website to be installed locally and be available on the app drawer and on the home screen of a phone. Today we will see how to use Angular Progressive Web App module to transform our app into a mobile app.

Angular

Cloudwatch Alarm On Disk Space

Mar 15th, 2019
CloudWatch Alarm on disk space used

Few weeks ago we saw how to configure CloudWatch to monitor upstream response time from logs. We create a CloudWatch configuration which allowed us to create metrics by parsing the logs and create a dashboard out of it. Building up from there, today we will see how we can monitor disk used space and trigger an alarm when the remaining disk space is critical.

AWS

Cycle Detection With Floyd Tortoise And Hare

Mar 6th, 2019
Floyd's Tortoise and Hare

Floyd’s Tortoise and Hare is a cycle detection algorithm operating on a linked list. The algorithm is based on two pointers, the tortoise and the hare, moving on the linked list at a different speed. The algorithm can be used to find cycle existence, deduces the beginning of the cycle, and the length of a cycle. Today we will explore the mathematical proof behind the algorithm and we will implement it in Racket.

Racket Python

The Basket Of Apples Problem With Tree

Mar 1st, 2019
The Basket of Apple Problem

Working with trees is an interesting task. Today we will look into the Basket of Apples problem, which can be solved using a tree structure. This deep dive will allow us to explore how we can reason around trees and understand concepts allowing us to vocalize ideas.

Mathematics

Fixed Point And Newton Method

Feb 22nd, 2019

Last week, we briefly looked into the Y Combinator also known as fixed-point combinator. Today we will explore more on the territory of fixed-points by looking at what a fixed-point is, and how it can be utilized with the Newton’s Method to define an implementation of a square root procedure.

Racket

Recursion With Fibonacci

Feb 14th, 2019

Recursion refers to the property of a function to be defined in term of itself. The Fibonacci sequence is a great example of a recursive problem where a Fibonacci number is calculated from a combination of precedent Fibonacci numbers. Recursion can be implemented in many forms, it is even possible to implement recursion without explicit self calling. Today we will look at different implementations of Fibonacci and discover their properties.

Racket

Lambda Calculus And Closure

Feb 6th, 2019

In programming, we often hear about Closures. Closures are present in any languages possessing functions as first class citizen. This includes functional languages and also widespread languages such as C#, Python and JavaScript. Today we will look at the origin of closures and understand what they are.

Racket
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