COSINE_TRANSFORM
A Discrete Cosine Transform for Real Data

COSINE_TRANSFORM is a C library which demonstrates some simple properties of the discrete cosine transform (DCT) for real data.

The code is not optimized in any way, and is intended instead for investigation and education.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

COSINE_TRANSFORM is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version and a Python version.

Related Data and Programs:

FFT_SERIAL, a C program which demonstrates the computation of a Fast Fourier Transform, and is intended as a starting point for implementing a parallel version.

HAAR, a C library which computes the Haar transform of data.

SFTPACK, a C library which implements the "slow" Fourier transform, intended as a teaching tool and comparison with the fast Fourier transform.

SINE_TRANSFORM, a C library which implements the discrete sine transform.

WALSH, a C library which implements versions of the Walsh and Haar transforms.

WAVELET, a C library which does some simple calculations with wavelet transforms;

Reference:

1. William Briggs, Van Emden Henson,
   The DFT: An Owner's Manual for the Discrete Fourier Transform,
   SIAM, 1995,
   ISBN13: 978-0-898713-42-8,
   LC: QA403.5.B75.
2. Eleanor Chu, Alan George,
   Inside the FFT Black Box,
   CRC Press,
   ISBN: 0849302706,
   LC: QA403.5C5.

Source Code:

• cosine_transform.c, the source code.
• cosine_transform.h, the include file.

Examples and Tests:

• cosine_transform_test.c, a sample calling program.
• cosine_transform_test.txt, the output file.

List of Routines:

• COSINE_TRANSFORM_DATA does a cosine transform on a vector of data.
• COSINE_TRANSFORM_INVERSE does an inverse cosine transform.
• R8VEC_UNIFORM_01 returns a unit pseudorandom R8VEC.
• TIMESTAMP prints the current YMDHMS date as a time stamp.

You can go up one level to the C source codes.