cWavelets is a small library to make computing discrete wavelet transforms (DWTs) easy. I apologize for the semi-OO style code written, but I wanted to leave it open for some expansions I have in mind for later down the road (OpenCL, MPI).

This library uses only the C Standard library, so you don't need to track down a bunch of esoteric libraries. I do use CMake to generate the Makefiles (or Visual Studio projects for WIndows (which is untested)) and run unit tests, so you will need to install that.

Run the autogen.sh script to create the build environment. Once it's done, change into the build directory and run make to build the library. If you would like to run the unit tests, run make test.

First include the wavelet.h header.

#include "wavelet.h"

Then create a wavelet object. inputData is an array of doubles representing your data. length is obviously the length of the data, and WAVELET is one of the wavelet constants.

waveletContainer *container = createWavelet(inputData, length, WAVELET);

Currently the Haar and Daubechies 2 through 10 wavelets are implemented. The constants for them are

HAAR_WAVELET
DAUBECHIES_N_WAVELET

where N is the number for the Daubechies wavelet. See the files in tests for further examples of instantiation.

To run the wavelet transform, call the transform() function on your wavelet container.

transform(container);

To access the data, access the output array. This is a circular array, as declared in circ_array.h. you can access using the ca_get() function, or you can access the data directly, such as container->output->arr[0].

When you are done with the wavelet container, destroy it with destroyWavelet(). This frees all memory associated with the container.

destroyWavelet(container);

For further examples, I suggest perusing tests.c, as I am aiming for 100% unit test coverage.

To add additional wavelets, there are a few steps you should take. First, define wavelet and scaling functions for your wavelet. See haar.c for a simple example of this. At this time, define an integer constant that uniquely identifies your wavelet. I used random numbers for this (see haar.h), but you can choose whatever number you wish, as log as it does not collide with a previously defined value.

Once this is done, add an else if clause to the createWavelet() function in wavelet.c. This defines parameters unique to your wavelet inside the wavelet container.

This software is licensed under a modified BSD license, typically referred to as a 3-clause BSD license. The full text form COPYING is reproduced below.

Copyright (c) 2011, William Ross All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the William Ross nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WILLIAM ROSS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS