Thank you for downloading the SPARCO toolbox! SPARCO is an environment for testing and benchmarking algorithms for sparse reconstruction. It includes a collection of sparse reconstruction problems that have appeared in the compressed sensing literature. The toolbox is also a framework for implementing new test problems, and includes a library of linear operators that appears in this context.
At the core of the sparse recovery problem is the linear system
A*x + r = b,
where A is an m-by-n linear operator and the m-vector b is the observed signal. The goal is to find a sparse n-vector x such that r is small in norm.
Please visit the Sparco GitHub page to download the latest version, and to see information on the test problems and operators.
SPARCO is prepackaged with all its required dependencies, but a few of the test problems may rely on external packages. These packages only need to be installed if you wish to use these particular problems.
The curevelet-based test problems 50-51 rely on the CurveLab toolbox.
Start Matlab and make sure that the working directory is set to the directory that contains the SPARCO source files. At the Matlab prompt, run
>> sparcoSetup
This script adds various directories to your Matlab path. The script will try to permanently add these directories to your path (in pathdefs.m), but may fail if that file is read-only. In that case, please copy and paste to your startup.m file the addpath commands printed to the screen.
To verify your installation, run
>> checkProblems
This script instantiates each of the test problems and does some quick testing to be sure all is in order.
The main interface to the test problems is through the main sparco script found at the top-level directory. To instantiate a particular test problem, simply call the main sparco script with the problems ID number or name. For example, to instantiate problem 5, do
>> prob = generateProblem(5);
or
>> prob = generateProblem('gcosspike');
This create a problem structure ('prob' in this case) which contains all the information needed to access this problem. This structure contains many bits and pieces, including function handles and data vectors. The most important component is
prob.A a function handle to the operator A
prob.b the right-hand-side vector
prob.sizeA tuple with the number of rows and columns in A
The function handle prob.A behaves as follows:
z = prob.A( x, mode ) gives z = A *x if mode == 1
z = A'*x if mode == 2
z = size(A) if mode == 0.
It is also possible to use the classOp tool to instantiate the operator as an overloaded object, e.g.,
>> C = classOp(prob.A); b = prob.b;
>> g = C'*b; # Equivalent to g = prob.A(b,2);
>> y = C *g; # Equivalent to y = prob.A(g,1);
The best way to get started is to browse the examples in the EXAMPLES subdirectory.
To get a full list of problem numbers, do
>> plist = generateProblem('list');
The conversion between problem name or number is done using for example
>> name = generateProblem(5,'getname');
>> index = generateProblem('gcosspike','lookup');
A list of test problems is maintained here.
SPARCO is open-source code released under the GNU Public License. We are delighted to acknowledge several other open-source packages that we could build on:
- Rice Wavelet Toolbox
- [Nonuniform FFT Toolbox(http://www.eecs.umich.edu/~fessler/code)
Several individuals have given kind permission to include section of code from their packages:
We hope that SPARCO proves useful in your experiments. If you have any bug reports or comments, please feel free to email one of the toolbox authors:
Ewout van den Berg <ewout78@cs.ubc.ca>
Michael P. Friedlander <mpf@cs.ubc.ca>