18 Dec 2014
We’ve scoured our database of more than 3 million payments to bring to you some cold, hard facts about Direct Debit. This should help you decide whether or not Direct Debit is right for you.
17 Dec 2014
How to build real-time publish/subscribe functionality into a go programming language application using PubNub and Golang SDK.
Online payments systems can be tough to understand. In this article, we demystify payments and recommend a range of alternative systems for those specific non-Direct Debit use cases.
How much overhead should we expect from enabling integer overflow checks? Using a compiler flag or built-in intrinsics, we should be able to do the check with a conditional branch that branches based on the overflow flag that add and sub set. Code that looks like add %esi, %edi should turn into something like add %esi, %edi jo <handle_overflow> Assuming…
This is a walk through of how to set up Google PageSpeed Insights within your existing gulp project. This way, you can get your page speed score information within your terminal without first needing to push your site to a live server.
16 Dec 2014
How to build an application with Python and JavaScript to fetch and stream report data from a MongoDB database.
We’re excited to launch a new series on our blog: the jOOQ Tuesdays. In this series, we’ll publish an article on the third Tuesday every month where we interview someone we find exciting in our industry from a jOOQ perspective. This includes people who work with SQL, Java, Open Source, and a variety of other … Continue reading jOOQ Tuesdays:…
15 Dec 2014
Securing a wireless home security system with Arduino, giving you a cheap way to keep an eye on your home from anywhere on Earth.
This is one of the more interesting recent Stack Overflow questions: Why does Iterable not provide stream() and parallelStream() methods? At first, it might seem intuitive to make it straight-forward to convert an Iterable into a Stream, because the two are really more or less the same thing for 90% of all use-cases. Granted, the … Continue reading Really Too…
The best place to start our journey through quantum computing is to recall how classical computing works and try to extend it. Since our final quantum computing model will be a circuit model, we should informally discuss circuits first. A circuit has three parts: the “inputs,” which are bits (either zero or one); the “gates,” which represent the lowest-level computations…
What is the half-life of programmer knowledge? It is quite common with claims that the half-life is something like 5 years. In other words, half of what you know about programming will be obsolete in 5 years. A similar sentiment … Continue reading →
Intro At Clay, our deploy process is fun. Seriously. Because we use Docker. Docker is a containerization tool that allows for easy application isolation and deployment. The basic idea is that Docker runs your application in a virtualized isolated environment, similar to a virtual machine, but without the overhead. You start with a 'base image', and then describe how to…
I will start this by quoting the bashstyle’s readme:
14 Dec 2014
A few months ago I saw a cool mosaic effect in a Wired ad for CA Technologies. Here’s what part of the ad looked like: I liked the ad, so I wondered how they did it. Can you see out how to create a similar effect? Take a minute to figure it out as an […]
Every once in a while I see somewhere a wrong import to the old, deprecated junit.framework instead of org.junit.
I've been doing a lot of research and experimentation lately about how people learn. This post might give you some ideas to improve your own comprehension and think about your own learning style.
13 Dec 2014
I have updated my unofficial ARM tarball distributions page with prebuilt Go 1.4 tarballs. You can find them by following the link in the main header of this page.
11 Dec 2014
In this program, the size of variables of type x and y in memory varies by platform. package main func main() { const n = 4 type x [n]uint type y [n]int } By changing only one line can you ensure that variables of type x, and y always consume 16 bytes on all platforms […]
Sometimes there are these moments of truth. They happen completely unexpectedly, such as when I read this tweet: Good discussion of Facebook Flow – http://t.co/5KTKakDB0w — David J. Pearce (@whileydave) November 23, 2014 David is the author of the lesser-known but not at all lesser-interesting Whiley programming language, a language that has a lot of … Continue reading The Inconvenient…
Direct debit is a great way for charities to collect payments and the three main providers are GoCardless, Valldata & Rapidata.
There are three main ways you can switch your customers over to GoCardless, which option is right for you will depend on a few things including whether you were already collecting Direct Debit payments and which GoCardless product you’re using.
10 Dec 2014
Bacstel-IP, Bacs approved software and the Bacs payment services website.
Back To School is the busiest time for any education company. Students, teachers, schools, software companies, and the rest of the education world are all gearing up for a new school year. Unfortunately, during the most critical time of the year, Clever’s infrastructure was throwing a fit. At the time, Clever was adding over a […] The post When your…
8 Dec 2014
Last Saturday our second Hackcamp Wolfsburg in 2014 took place. In the run-up to the Hackcamp I had suggested to use the NeosIT office as the event location. @stevenschwenke agreed to that and so I prepared our office on Friday evening. Before the event I expected a team programming session but […] The post Second Hackcamp Wolfsburg – December 2014…
From time to time, I find someone using the double curly braces anti pattern (also called double brace initialisation) in the wild. This time on Stack Overflow: In case you do not understand the syntax, it’s actually easy. There are two elements: We’re creating anonymous classes that extend HashMap by writing In that anonymous class, … Continue reading Don’t be…
I’m working on a project that requires Geo proximity search. Basically, what I’m doing is plotting a radius around a point on a map, which is defined by the distance between two points on the map given their latitudes and longitudes. To achieve this I’m using the Haversine formula (spherical trigonometry). This equation is important […]
Quantum mechanics is one of the leading scientific theories describing the rules that govern the universe. It’s discovery and formulation was one of the most important revolutions in the history of mankind, contributing in no small part to the invention of the transistor and the laser. Here at Math ∩ Programming we don’t put too much emphasis on physics or…
This week I will give a presentation at a local high school on what it is like to work as a programmer. I am volunteering (through the organization Transfer) to come to schools and talk about what I work with. … Continue reading →
Now that the Visual Studio 2015 Preview is available and the C# 6 feature set is a bit more stable, I figured it was time to start updating the Noda Time 2.0 source code to C# 6. The target framework is still .NET 3.5 (although that might change; I gather very few developers are actually … Continue reading C# 6…
6 Dec 2014
Our software allows you to view MBTiles file offline.
5 Dec 2014
It’s a little unfair to announce winners in some kind of order as I did post the quiz at an unfriendly hour of the day for most of the planet. With that said, Tim and William came up with a great map based solution at roughly the same time. You’ll have to split the winnings […]
This program is incorrect package main import "fmt" func f(a, b int) { var min = 0 fmt.Printf("The min of %d and %d is %d\n", a, b, min) } func main() { f(9000, 314) } By adding only one line can you make it print the correct answer ? The code must continue to be […]
4 Dec 2014
There are some things in SQL that we simply take for granted without thinking about them properly. One of these things are the GROUP BY and the less popular HAVING clauses. Let’s look at a simple example. For this example, we’ll reiterate the example database we’ve seen in this previous article about the awesome LEAD(), … Continue reading Do You…
Let's write a malloc and see how it works with existing programs! This is basically an expanded explanation of what I did after reading this tutorial by Marwan Burelle and then sitting down and trying to write my own implementation, so the steps are going to be fairly similar. The main implementation differences are that my version is simpler and…
2 Dec 2014
According to a recent survey by ZeroTurnaround’s RebelLabs, Maven is still the leading Java build platform. The current market share distribution, according to RebelLabs is: Maven with 64% Ant + Ivy with 16.5% Gradle with 11% Yet, at the same time, Maven is often criticised for being a bit obscure and intrusive. Compared to runner-ups … Continue reading How to…
I’m confused. For many years I’ve been a .NET / Microsoft stack developer (from now on I might call it .NET for simplicity, but what I mean is the Windows / ASP / .NET / IIS / SQL Server etc. The post To .NET or not to .NET, That is the Question appeared first on FullStack - Ofer Zelig's Blog.
Recently we teamed up with Concurrent Inc., the backers of the data-processing framework Cascading, to do a case study of how we use…
1 Dec 2014
Here’s a few things you may not be aware of: C# identifiers can include Unicode escape sequences (\u1234 etc) C# identifiers can include Unicode characters in the category “Other, formatting” (Cf) but these are ignored when comparing identifiers for equality The Mongolian Vowel Separator (U+180E) has oscillated between the Cf and Zs categories a couple … Continue reading When is…
"Invalid Username or Password": a useless security measure Login attempts fail because computer users can't remember their email or didn't input the right password. Most websites on the Internet won't tell you which one is actually incorrect. Amazon: Shoprunner: Hacker News: If you tell an attacker the email address is wrong, they'll try a different […]
In the last post in this series we saw some simple examples of linear programs, derived the concept of a dual linear program, and saw the duality theorem and the complementary slackness conditions which give a rough sketch of the stopping criterion for an algorithm. This time we’ll go ahead and write this algorithm for solving linear programs, and next…
If you’ve read Scott Adams’ financial advice and my financial tips in case you win a startup lottery, then you might be interested in a few more pointers to good resources. Some web pages and books: – Don’t Play the Losers’ Game, by Henry Blodget. This is a short, accessible piece that explains why picking […]
I’ve been spending more time surfing the web on my laptop than I’d like to. I’ve also noticed more emails that lure me into short tasks, but eventually eat up a large chunk of my day. I’d prefer to be spending more time working on projects, reading, and unplugging. So my new 30 day challenge […]
So how did I do on my 30 day writing challenge? Well, the picture tells the story: Not too bad! I did miss one day, but here’s a secret about 30 day challenges: if you miss a day or two, you can just keep doing the challenge for another day or so at the end. […]
After lurking on the fringes of the hobbyist electronic and retrocomputing communities for a few years I’ve decided to take the plunge and join the RC2015/01 retrochallenge. The task I have assigned myself is to revive this 1981 vintage revision 7 Apple II motherboard which I discovered in a box of parts while visiting my […]
Public discussions of discrimination in tech often result in someone claiming that discrimination is impossible because of market forces. Here's a quote from Marc Andreessen that sums up a common view1. Let's launch right into it. I think the critique that Silicon Valley companies are deliberately, systematically discriminatory is incorrect, and there are two reasons to believe that that's the…
30 Nov 2014
The question of how to set up a new Go project appears commonly on the golang-nuts mailing list. Normally the advice for how to structure Go code centres around “read the standard library”, but the standard library is not a great deal of use to newcomers in the respect as: You don’t go get packages […]
Working in webspam, we sometimes use the phrase “buy Viagra online” as an example of a search query that might be spammy. That’s why I noticed and remembered the 2013 announcement that you can officially buy Viagra online. As this Time article points out, you’ve actually been able to buy Viagra online through legitimate pharmacy […]
Because not every blog post has to be serious: Special thanks to my friend Amy who crocheted this masterpiece! Amy also works with an awesome group of volunteers that crochets dolls for kids fighting cancer and other illnesses.
29 Nov 2014
Recently I had a very weird problem with iTerm where new login shells were being created with environment variables already present. Restarting my machine made the issue go away, and I wasn't able to reproduce it again. But I got curious about how long ZSH spends in various parts of the startup process. A new […]
Any time you talk about money, you risk sounding like a jerk. I’m going to take that risk in this post. I’ll start out by talking about a couple ways I shot myself in the foot financially and what I learned as a result. Your mileage may vary. Before we start, you might want to […]
28 Nov 2014
I’m thankful for family and friends and good health and so many wonderful people I’ve had the pleasure of working with at Google. But I’m also thankful for airplanes: “You want to see your family? It would take months to walk to them, but come sit in this metal tube and thanks to some interesting […]
27 Nov 2014
One of the best things about modern cryptography is the beautiful terminology. You could start any number of punk bands (or Tumblrs) named after cryptography terms like ‘hard-core predicate’, ‘trapdoor function’, ‘ or ‘impossible differential cryptanalysis’. And of course, I haven’t even mentioned the one term that surpasses all of these. That term is ‘zero knowledge‘. In … Continue reading…
Hello! This blog post is going to go over how to create a Linux partition on your mac and have everything working successfully. Okay so lets begin with: sudo rm -rf / && sudo kill -9 1. Hold the phone. That was a test. I really hope you didn’t just copy, paste, and run a command on your host without…
I’m looking at this list of federal holidays, and you know what I’m thinking? I’m thinking fuck Columbus Day. Who the hell cares about Columbus Day except for mattress stores? Instead, let’s scratch Columbus Day and make Election Day a national holiday. Turnout on Election Day was only 36.6 percent in 2014, according to Senator […]
26 Nov 2014
Evangelist Sunny Gleason shares a set of new, open source ElasticSearch plugins that he's built for multi data center ElasticSearch replication
Google has a pretty good culture of doing postmortems. When something fails, someone close to the failure tries to document what happened and why. A good postmortem document should also point the way to avoid similar mistakes in the future. Mistakes happen, but you don’t want to make the same mistakes over and over again. […]
25 Nov 2014
The story of how I built a model house that can be controlled from anywhere on Earth with Arduino using PubNub
I had one more experience at the XOXO Festival that I wanted to mention. I really enjoyed Anita Sarkeesian’s talk. You can watch it here: Sarkeesian explained her experience with humor and grace, and that really resonated with me. I don’t want to join the tone police–passionate voices have a role in this discussion too, […]
24 Nov 2014
This quick start shows how to implement ElasticSearch plugins to use as a medium for cross-cluster document real-time geo-replication and indexing.
Open source is really good at creating products. Almost any commercial software package or product like Word, Excel, Windows, or Photoshop has a great open source equivalent. However, open source has been less successful at creating services. Where’s the open source version of Google, or Facebook, or Twitter, or Gmail, or Craigslist? You could sum […]
I was curious what different people worked on in Linux, so I tried grabbing data from the current git repository to see if I could pull that out of commit message data. This doesn't include history from before they switched to git, so it only goes back to 2005, but that's still a decent chunk of history. Here's a list…
23 Nov 2014
If you’re a geek like me, there’s probably a bank or cluster of micro USB chargers somewhere in your house for recharging phones, tablets, Kindles, headphones, etc. Lately I’ve been playing with a couple USB chargers that I really like. One is a USB charger with 3.5 amp (!) output. Just for context, a typical […]
22 Nov 2014
Every year or so, it’s worthwhile doing an audit of your online security. The most important accounts to protect are your bank accounts and your email accounts. Here are some things to consider doing: – Choose strong passwords. Just as important: don’t re-use the same password across web services. Consider using a password manager like […]
21 Nov 2014
This tutorial shows how to stream sensor readings in real time using the Texas Instrument LaunchPad, Energia, and PubNub
Juju is a pretty large project. Some of our core packages have large complex dependency graphs and this is undesirable because the packages which import those core packages inherit these dependencies raising the spectre of an inadvertent import loop. Reducing the coupling between our core packages has been a side project for some time for me. […]
Take a look at the 5 main options for taking payments in Europe.
When I was in grad school in the late 90s, not very much scholarly work was on the web. I had to walk over to the campus library to access scholarly papers, and sometimes make photocopies of the physical papers I wanted. Things have gotten better, but it’s still harder to do research than it […]
20 Nov 2014
This blog post walks you through how to build a fully featured chat application that is optimized for customer facing sales and support purposes.
MySQL is a database that has been bending the SQL standard in ways that make it hard to move off MySQL. What may appear to be a clever technique for vendor lockin (or maybe just oversight of the standard) can be quite annoying in understanding the real meaning of the SQL language. One such example … Continue reading Use MySQL’s…
The week before XOXO, a festival dedicated to independent artists and creators, I was in Juneau, Alaska for a cruise with my wife and my parents. I got off the ship with my Dad and we walked around town. We kept walking, past the touristy stores selling smoked salmon and tanzanite. We walked for a […]
19 Nov 2014
The state of Kentucky has 120 counties. It has so many because the idea was that you should be able to make it to the county seat and back in a single day. That speaks to how isolated people used to be. Likewise, the Galapagos Islands are known for their diversity, in part because the […]
We released a video on how to create a Google Earth KML SuperOverlay.
When designers and developers work together from the start, it produces better outcomes. But how can we get designers involved and wanting to participate in the open source community from the start?
18 Nov 2014
This tutorial shows you how to build a real-time voting app that broadcasts live results as votes come in using D3js and PubNub Data Streams.
Problem: Alice chooses a secret polynomial $ p(x)$ with nonnegative integer coefficients. Bob wants to discover this polynomial by querying Alice for the value of $ p(x)$ for some integer $ x$ of Bob’s choice. What is the minimal number of queries Bob needs to determine $ p(x)$ exactly? Solution: Two queries. The first is $ p(1)$, and if we…
This weekend I swapped comic book recommendations with a few folks. Today I was emailing someone a few of my favorites and thought “I should just put this up on the blog.” So to call out a few comics I’ve enjoyed: – Sandman – the classic Neil Gaiman books that make it “okay” to be a […]
Have you ever written JUnit tests extending a class that does some before and after work, so you didn’t have to repeat that code in various test classes?
If I had to guess, I'd say I probably work around hundreds of bugs in an average week, and thousands in a bad week. It's not unusual for me to run into a hundred new bugs in a single week. But I often get skepticism when I mention that I run into multiple new (to me) bugs per day, and…
17 Nov 2014
Imagine that you’re training for the San Francisco Marathon. You’d like to prepare for the distinctive pattern of hills on the course: Now if you live in San Francisco, you could just run along the actual race course. But what if you don’t live near San Francisco? Wouldn’t it be cool if a service could […]
I've seen all these studies that show how a 100ms improvement in page load time has a significant effect on page views, conversion rate, etc., but I'd never actually tried to optimize my site. This blog is a static Octopress site, hosted on GitHub Pages. Static sites are supposed to be fast, and GitHub Pages uses Fastly, which is supposed…
Over the weekend I spoke at the Embergarten Saturday Symposium, which was an awesome mini conference on Ember in Toronto. My topic was “Ember at 10ft”, and it was about how to build a TV friendly interface in Ember.js. The talk was recorded but not yet posted, however I’ve already posted the source code on github. The github repo contains…
The SoundCloud API will be dropping support for Extensible Markup Language (XML) responses. XML will be phased out on the following schedule…
15 Nov 2014
Here’s something that I wrote internally within Google in mid-2013. I think at the time, folks within Google were discussing XMPP. The discussion wasn’t as much about client-to-server XMPP, but server-to-server XMPP, which is a less followed area. Anyway, here’s the internal post I wrote: We want to compete on a level playing field We’ve […]
14 Nov 2014
I recently had a web page with a long list of Twitter names that were not linked, like @mattcutts. I thought that someone has to have made a Chrome extension that would “linkify” names so they would be clickable like @mattcutts. And with a little bit of searching, I found twlinkfy. It looked like a […]
This blog post gives an overview of a data firehose API, how it works, use cases, and how to build one yourself from any data source.
We’ve recently encountered this interesting use-case on the jOOQ user group. How do you discover all primary keys of your schema via the jOOQ API? There are two ways: Using the generated meta data Using runtime meta data Let’s see how it works: Using the generated meta data This is straightforward. If you’re using Java … Continue reading jOOQ Tip…
13 Nov 2014
One trick that I’ve discovered pretty recently for my 30 day challenges is based on advice from Jerry Seinfeld. The idea is that you get yourself a cheap calendar and a red pen. Every day you complete your daily challenge, you can cross that day off with a satisfying swipe of the red pen. Once […]
With remote configuration, you can control smart devices from anywhere. This tutorial shows you how to do it with Raspberry Pi, Arduino, and a browser
History is an angel being blown backwards into the future. History is a pile of debris, and the angel wants to go back and fix things, to repair things that have been broken. But there is a storm blowing from Paradise, and this storm keeps blowing the angel backwards into the future. And this storm […]
Klokan Technologies GmbH team, in cooperation with CampToCamp and BoundlessGeo, designed and implemented a binding between the OpenLayers and Cesium projects allowing to display maps in 3D.
An alphabetized list of styleguides and pattern libraries and a look into the differences between those two terms.
Our new website for Austin's Sass Meetup is live!
12 Nov 2014
This tutorial shows you how to build a second screen game in a web browser with JavaScript that uses a phone controller.
Now that I have your attention, I’d like to invite you to a critical review of where we’re at in the MySQL vs. MariaDB debate. Around one month ago, I visited Oracle Open World 2014, and I’ve met with Morgan Tocker, the MySQL community manager at Oracle to learn about where MySQL is heading. Who … Continue reading Don’t Migrate…
Merchants often ask us for help getting their customers set up to use Direct Debit, so we've put together six simple steps that you can use to help them through the process.