https://github.com/paxswill/cwavelet

A C Library for running DWTs
https://github.com/paxswill/cwavelet

Last synced: about 2 months ago
JSON representation

A C Library for running DWTs

• Host: GitHub
• URL: https://github.com/paxswill/cwavelet
• Owner: paxswill
• License: other
• Created: 2011-03-27T09:20:49.000Z (about 14 years ago)
• Default Branch: master
• Last Pushed: 2011-10-28T08:00:32.000Z (over 13 years ago)
• Last Synced: 2025-03-27T04:33:29.554Z (3 months ago)
• Language: C
• Homepage:
• Size: 219 KB
• Stars: 6
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: COPYING

Awesome Lists containing this project

README

        
# cWavelets

**cWavelets** is a small library to make computing [discrete wavelet transforms](http://en.wikipedia.org/wiki/Discrete_wavelet_transform) (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).

## Prerequisites

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](http://www.cmake.org/) to generate the Makefiles (or Visual Studio projects for WIndows (which is untested)) and run unit tests, so you will need to install that.

## Compiling

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`.

## Usage

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.

## Extending

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.

## License

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