A+ is a powerful and efficient programming language. It embodies a rich set of functions and operators, a modern GUI with many widgets and automatic synchronization of widgets and variables, asynchronous execution of functions associated with variables and events, dynamic loading of user compiled subroutines, and many other features. Execution is by a rather efficient interpreter.
Cactus is a general, modular, parallel environment for solving systems of partial differential equations. The code has been developed over many years by a large international collaboration of numerical relativity and computational science research groups and can be used to provide a portable platform for solving any system of partial differential equations.
The Date::Calc package consists of a (pure-Perl) wrapper which either loads Date::Calc::XS (a separate implementation in C and XS) or Date::Calc::PP (a pure-Perl implementation which is part of the Date::Calc package). The Date::Calc::XS and Date::Calc::PP modules perform all kinds of date calculations based on the Gregorian calendar (the one used in all Western countries today), according to relevant norms and standards: ISO/R 2015-1971, DIN 1355 and, to some extent, ISO 8601 (where applicable). The package is designed as an efficient toolbox, not a bulky ready-made application. It provides extensive documentation and examples of use, multi-language support, and special functions for business needs.
The Date::Pcalc Perl module is a direct translation of Steffen Beyer's excellent Date::Calc module from a combination of C and Perl to Perl only. The Perl module does all kinds of date calculations based on the Gregorian calendar (the one used in all western countries today), thereby complying with all relevant norms and standards: ISO/R 2015-1971, DIN 1355 and, to some extent, ISO 8601 (where applicable).
FFTW is a fast C FFT library. It includes complex, real, symmetric, multidimensional, and parallel transforms, and can handle arbitrary array sizes efficiently.It is typically faster than other freely available FFT implementations, and is even competitive with vendor-tuned libraries (benchmarks are available at the homepage). To achieve this performance, it uses novel code generation and runtime self optimization techniques (along with many other tricks).