An alternating direction method for second-order
conic programming
$
Xuewen Mu
a,
n
, Yaling Zhang
b
a
Department of Mathematics, Xidian University, Xi’an, 710071, China
b
Department of Computer Science, Xi’an Science and Technology University, Xi’an, 710054, China
article info
Available online 18 January 2013
Keywords:
Second-order cone programming
Dual augmented Lagrangian method
Alternating direction method
Primal-dual interior point method
abstract
An alternating direction dual augmented Lagrangian method for second-order cone programming
(SOCP) problems is proposed. In the algorithm, at each iteration it first minimizes the dual augmented
Lagrangian function with respect to the dual variables, and then with respect to the dual slack variables
while keeping the other two variables fixed, and then finally it updates the Lagrange multipliers.
Convergence result is given. Numerical results demonstrate that our method is fast and efficient,
especially for the large-scale second-order cone programming.
& 2013 Elsevier Ltd. All rights reserved.
1. Introduction
Second-order cone programming (SOCP) is to minimize a
linear function over the intersection of an affine set and the
product of second-order cones. SOCP is nonlinear convex pro-
gramming problem, and the linear and convex quadratic pro-
grams are special cases.
We consider the primal SOCP problem
ðPÞ minfc
T
x : Ax ¼b, xA Kg,
where A ¼ðA
1
, A
2
, ..., A
N
ÞA R
mn
, c ¼ðc
T
1
, c
T
2
, ..., c
T
N
Þ
T
A R
n
, A
i
A R
mn
i
,
c
i
A R
n
i
, bA R
m
are scalars, and x ¼ðx
T
1
, x
T
2
, ..., x
T
N
Þ
T
A R
n
, x
i
A R
n
i
is
variable. In the same time, K ¼K
1
K
2
K
N
and
P
N
i ¼ 0
n
i
¼n.
In addition, x
i
A K
i
, and K
i
is the standard second-order cone of
dimension n
i
, which is defined as
K
i
¼ x
i
¼
x
i1
x
i0
!
A R
ðn
i
1Þ
R : Jx
i1
J
2
r x
i0
()
,
where J J
2
is the standard Euclidean norm, i:e: JuJ
2
¼ðu
T
uÞ
1=2
for
uA R
n
. Without loss the generality, we assume that N ¼ 1, K
1
¼K.
The dual problem of the primal SOCP is [1,2]
ðDPÞ maxfb
T
y : A
T
yþz ¼ c, zA Kg,
where yA R
m
are vector variables.
There are many applications in the engineering for the SOCP,
such as FIR filter design, antenna array weight design, truss design
[2–5]. There have been many methods proposed for solving SOCP
and second-order cone complementarity problem. They include
interior-point methods [6–10], the smoothing Newton methods
[11,12], the merit function method [13] and the semismooth
Newton method [14], where the last three kinds of methods
are all based on an SOCP complementarity function or a merit
function. The primal-dual interior point method is a second-order
method, so at each iteration we need compute a equation system.
The alternating direction method (ADM) has been an effective
first-order approach for solving large optimization problems with
vector variables. It probably first arises from partial differential
equations (PDEs) [15,16]. In these methods, the variables are
partitioned into several blocks, and then the function is mini-
mized with respect to each block by fixing all other blocks at each
inner iteration. The idea has been developed for many optimization
problems, such as, variational inequality problems [17–19], linear
programming [20], semidefinite (SDP) programming [31,38,27 ], non-
linear convex optimization [22,25,26,28], and nonsmooth l
1
mini-
mization arising from compressive sensing [29,30]. In [31],an
alternating direction method for SDP is presented by reformulating
the complementary condition as a projection equation. In paper [38],
based on a single inexact metric projection onto the positive
semidefinite cone at each iteration, the author proposes a modified
alternating direction method for convex quadratically constrained
quadratic semidefinite pro grams. In paper [32], an alternating direc-
tion dual augmented Lagrangian method for solving semidefinite
programming problems in standard form is presented and is
extended to separately minimize the dual augmented Lagrangian
function SDP with inequali ty constraints and positivity constraints.
These new research results show that the alternating
direction method are very efficient for some optimization pro-
blems. But to now, there is not any alternating direction method
for second-order cone programming. Although second-order cone
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journal homepage: www.elsevier.com/locate/caor
Computers & Operations Research
0305-0548/$ - see front matter & 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.cor.2013.01.010
$
The short running title is ADM for SOCP.
n
Corresponding author. Tel./fax: þ86 29 88202860.
E-mail addresses: xdmuxuewen@hotmail.com (X. Mu),
zyldella@xust.edu.cn (Y. Zhang).
Computers & Operations Research 40 (2013) 1752–1757