XCode is an application (Integrated Development Environment) produced by Apple Inc. It provides an interface for the gcc (GNU) compiler. XCode is available for free at the Apple website.
Clapack is a library of linear algebra subroutines. It was produced by translating the Fortran library called Lapack into C via a tool called f2c. Clapack is available for free at www.netlib.org. Clapack is automatically included (as the vecLib Framework) in the standard installation of MacOS X .
Qubiter (US Patent 6,456,994 ) is a computer program that can decompose an arbitrary unitary matrix (Well, as long as it's not too big) into a SEO (sequence of elementary operations---operations such as controlled-nots and qubit rotations). Such SEOs are used to manipulate an array of quantum bits (i.e. a quantum computer.) The mathematics behind Qubiter is explained in: "A Rudimentary Quantum Compiler(2cnd Ed.)", by R. R. Tucci, arXiv eprint quant-ph/9902062. Additional references can be found here. Qubiter is brought to you courtesy of the Artiste Company, makers of Quantum Fog.
VERY IMPORTANT: Before starting to use Qubiter 1.11, you must first read and agree with the Qubiter license. You can find it in the file entitled "Qbtr1.11_License.txt"
In its current version 1.11, Qubiter is fairly crude---a pure C++ program with no GUI. It's just a research tool, so don't expect too much. The Qubiter 1.11 distribution includes an XCode 2.4 project file. Qubiter is linked to the Clapack library.
Since Qubiter 1.11 is pure C++, you don't need XCode, or even Mac OS X to use it: you can run Qubiter on any platform for which you have a C++ compiler. However, if you don't use XCode, you will have to write your own makefile or project file. Furthermore, if you do not use MacOS X, you will have to install the Clapack library in your computer, if it isn't installed already, as it is in Macs.
Henceforth we will use "MATNAME" as a prefix in file names. For example, we will speak of a file called "MATNAME-engl.in". You should replace MATNAME by a name that identifies the particular matrix being analyzed. For example, you might use "FT3bits-engl.in" instead of "MATNAME-engl.in" if you are dealing with 3 bit Fourier Transform matrices.