MyMediaLite is a lightweight, multi-purpose library of recommender system algorithms. It addresses the two most common scenarios in collaborative filtering: rating prediction (e.g. on a scale of 1 to 5 stars), and item prediction from implicit feedback (e.g. from clicks or purchase actions). It contains dozens of recommender engines, including state-of-the-art matrix factorization methods. It also supports real-time updates to the recommender engines, storing engines to disk and reloading them again, and several evaluation measures to compare the accuracy of different recommender system methods. Three command-line programs that offer most of the functionality contained in the library are included.
PhysicsFS is a library to provide abstract access to various archives. The programmer defines a "write directory" on the physical filesystem. No file writing done through the PhysicsFS API can leave that write directory, for security. For file reading, the programmer lists directories and archives that form a "search path". Once the search path is defined, it becomes a single, transparent, hierarchical filesystem. This makes for easy access to ZIP files in the same way as you access a file directly on the disk, and it makes it easy to ship a new archive that will override a previous archive on a per-file basis. Symbolic links can be disabled, for added safety. Finally, PhysicsFS gives you a platform- abstracted means to determine if CD-ROMs are available, the user's home directory, where in the real filesystem your program is running, etc.
Valentina is cross-platform SQL and non-SQL columnar database that allows development of client-server [Web] solutions and applications with an embedded local database using the same sources. Valentina DB provides an Object-Relational model, but you can also mix Relational and Extended Navigational. It introduces a revolutionary model abstraction "Link" that greatly simplifies db schema, and therefore simplifies SQL queries. It supports disk and in-memory databases, and field types including Bit, BLOB, Pictures, and Enum. It provides advanced features such as triggers, views, stored procedures, regular expressions, XML, full-text search, and calculated fields. It exists as Valentina Server, Valentina Studio, and a set of Valentina ADKs for all major programming languages.
Virtual Print Engine Community Edition is a report generator, print engine, and PDF library. It allows you to create documents like reports, forms, drawings, and diagrams on-the-fly by placing objects like text, lines, and bitmaps in any position using function calls. Flexible dynamic layouts are supported. Documents containing tens of thousands of pages can be created with a very small memory footprint. New documents can be assembled from several single documents.
Xapian is a search engine library, scalable to collections containing hundreds of millions of documents. It's written in C++ with bindings for Perl, Python, PHP, Java, Tcl, C#, Ruby, and Lua. It is a highly adaptable toolkit that allows developers to easily add advanced indexing and search facilities to their own applications. It supports the Probabilistic Information Retrieval model and also a rich set of boolean query operators. Omega is a Web search application built upon the Xapian library. It can index a Web server's document tree (including HTML, PDF, OpenOffice, MS Word/Excel/Powerpoint/Works, WordPerfect, RTF, PS, etc.), or data exported from arbitrary sources (e.g. SQL databases).