Residential Real Estate Listing Price and Sales Price Disconnect

Asking Price Clusters Around Home Features; Sales Price doesn't

Save your data, even if your project is half-baked and you think your done with it. Years ago in 2014 I got access to an interesting dataset, and used it to come up with some potentially useful conclusions about valuing homes for sale. For whatever reason, today I remembered the work and went to dig up the data and project files to refine the queries and create a model… only to discover the data is permanently gone. [Read More]

Rust Ownership

Comparisons to Other Languages

While learning Rust you encounter the “borrow checker” and the concept of ownership. The borrow-checker automatically does checks you’d probably be doing in your head when programming in other non-garbage collected languages anyway. If you don’t think about ownership when coding in C++, C or Pascal, for instance, you may end up debugging strange behavior or segmentation faults when you run your programs. [Read More]

Optimization Part V: Applying Data Oriented Design Principles

Optimizing Data Flow on a Data Intensive C++ Application

Today I’m going to focus on data-oriented design inspired optimizations. Previously, I also did a handful of API improvements made obvious from a flame graph profile, and then replaced all uses of the STL “unordered_map” type with a more efficient implementation of a flat hash map. [Read More]

Notes for a Sequel/JRuby/SQLite Bug

A Bug in Sequel, JRuby + SQLite DATETIME type columns

Accessing SQLite3 DATETIME column data with the Sequel gem “jdbc” SQLite adapter produces different date types for the DATETIME columns than does the MRI Sequel adapter. So, you get ‘Time’ objects in the result sets when using standard Ruby, but ‘Date’ types when using JRuby. The ‘Date’ objects don’t have a time component; the ‘Time’ objects have both date and time. [Read More]

Developing Software is Developing Knowledge

Why Agile Methodologies Work

Software development is the art of transforming vague requirements into precise statements executible by a machine, resulting in a working software system. Almost by definition you can’t begin a project with perfect requirements; if you did so they would be executible or translatable on their own with no need for further development. The reason “Agile” development methodologies have persisted is that they are designed around this basic truth. [Read More]