CVX: Matlab Software for
Disciplined Convex Programming

Introduction

CVX is a Matlab-based modeling system for convex optimization. CVX turns Matlab into a modeling language, allowing constraints and objectives to be specified using standard Matlab expression syntax. For example, the following code segment randomly generates a constrained norm minimization problem, and solves it:

m = 20; n = 10; p = 4;
A = randn(m,n); b = randn(m,1);
C = randn(p,n); d = randn(p,1);
cvx_begin
    variable x(n)
    minimize( norm( A * x - b, 2 ) )
    subject to
        C * x == d;
        norm( x, Inf ) <= 0.4;
cvx_end

In its default mode, CVX supports a particular approach to convex optimization that we call disciplined convex programming. Under this approach, convex functions and sets are built up from a small set of rules from convex analysis, starting from a base library of convex functions and sets. Constraints and objectives that are expressed using these rules are automatically transformed to a canonical form and solved. For more information on disciplined convex programming, see these resources; for the basics of convex analysis and convex optimization, see the book Convex Optimization.

CVX also supports geometric programming (GP) through the use of a special GP mode. Geometric programs are not convex, but can be made so by applying a certain transformation. In this mode, CVX allows GPs to be constructed in their native, nonconvex form, transforms them automatically to a solvable convex form, and translates the numerical results back to the original problem.

More information about CVX can be found in the CVX Users’ Guide (pdf, 404KB).

The CVX package includes a growing library of examples to help get you started, including examples from the book Convex Optimization and from a variety of applications. You can browse through this library now—without having to download and install CVX—by clicking here.

Latest news

Fuller support for 64-bit platforms

CVX version 1.2 now supports 64-bit versions of Matlab on Windows, Linux, and Macintosh platforms; precompiled MEX files are supplied for each of these platforms. Previously, only SDPT3 was supported on 64-bit platforms; now SeDuMi is as well. However, due to the evolution of Matlab’s MEX API, Matlab version 7.3 or later is required for 64-bit platforms; and SeDuMi requires version 7.5 or later. (Earlier versions of Matlab are still supported for 32-bit platforms.)

Support for the exponential family of functions

CVX version 1.2 now supports problems involving exponentials, logarithms, and entropy functions! A novel successive approximation approach has been developed to facilitate this improvement. Please see the user’s guide for more details.

Notice to users of Matlab R12.1 (6.1)

In order to facilitate some upcoming developments for CVX, we have decided that it will be necessary to discontinue support for Matlab 6.1. This change will occur at some point this summer, at which point CVX will require the use of Matlab version 6.5 or newer. If you currently use Matlab 6.1, please contact us to discuss alternatives.