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mex interface for bound constrained optimization via ASA

version 1.2 (10.9 KB) by

ASA solves bound constrained problems; the user provides routines to calculate the function and grad



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ASA (Active-Set Algorithm) is a bound constrained optimization program developed W. W. Hager and H. Zhang. In recent academic tests (e.g. "Evaluating bound-constrained minimization software" by E. Birgin and J. Gentil, 2011) it has been shown to be very fast (even faster than L-BFGS-B).

The original code (see and is written in C. This Matlab package is a mex gateway routine, along with a simple sample file that gets you started.

It requires you to compile with the mex compiler, but there are no necessary libraries, so if you have a C compiler, it should be very straightforward.

The test_ASA.m file installs everything: it downloads the C files, and it runs the mex compiler. The file also has a little test, and it shows how to make an example with non-negative least-squares (NNLS). For the NNLS problem, I include 3 driver routines that use an additional input of parameters so that you can re-use those functions even when parameters change; this trick should be useful for other problems.

The ASA method uses an active-set approach, and a state-of-the-art non-linear CG algorithm ("cg_descent") to solve the subproblems. Info available at

This mex interface works with v2.2 of their code; there are no guarantees it will work with a future version. It should work with any version of Matlab.

Comments and Ratings (2)


neiho (view profile)

Links are dead. Could you give new ones? Thank you:)



The new mex file is compatible with a wider variety of compilers now


Making it more powerful by allowing extra options parameter, and showing an example with NNLS. Also incorporating suggestions by James Tursa.

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