Matlab cvx 错误与 cvx_begin

Question

cvx由于某种原因，对我来说不能开箱即用。

我使用 Windows x64、cvx x64 和 Matlab x64 R2012a

但是当我运行简单的示例(\cvx\examples\quickstart.m)时，它会给我一个错误:

>> quickstart

has_quadprog = exist( 'quadprog' );
has_quadprog = has_quadprog == 2 | has_quadprog == 3;
has_linprog  = exist( 'linprog' );
has_linprog  = has_linprog == 2 | has_linprog == 3;
rnstate = randn( 'state' ); randn( 'state', 1 );
s_quiet = cvx_quiet(true);
s_pause = cvx_pause(false);
cvx_clear; echo on

prob = evalin( 'caller', 'cvx_problem', '[]' );
if isa( prob, 'cvxprob' ),

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% SECTION 2.1: LEAST SQUARES %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Input data
m = 16; n = 8;
A = randn(m,n);
b = randn(m,1);

% Matlab version
x_ls = A \ b;

% cvx version
cvx_begin
Attempt to reference field of non-structure array.

Error in cvxprob (line 48)
    selected = cvx___.solvers.selected;

Error in cvx_begin (line 41)
assignin( 'caller', 'cvx_problem', cvxprob( varargin{:} ) );

Error in quickstart (line 25)
cvx_begin

Answer 1

安装比较简单:

1. 下载 CVX(我获得的 cvx-rd.zip 发行版仅包含免费求解器，其中包含适用于所有支持平台的预编译 MEX 二进制文件)。

2. 将 ZIP 文件解压到某个位置，例如 C:\cvx

3. 导航到 MATLAB 中的该目录，然后运行 ​​cvx_setup:

   >> cd('C:\cvx')
   >> cvx_setup
   
   ---------------------------------------------------------------------------
   CVX: Software for Disciplined Convex Programming       (c)2014 CVX Research
   Version 2.1, Build 1088 (e790d80)                  Sat Sep 20 22:03:02 2014
   ---------------------------------------------------------------------------
   Installation info:
       Path: C:\cvx
       MATLAB version: 8.3 (R2014a)
       OS: Windows 8 amd64 version 6.2
       Java version: 1.7.0_11
   Verfying CVX directory contents:
       No missing files.
   Preferences: none found; defaults loaded.
   ---------------------------------------------------------------------------
   Setting CVX paths...done.
   Saving updated path...done.
   Searching for solvers...3 shims found.
   2 solvers initialized (* = default):
    *  SDPT3    4.0     {cvx}\sdpt3
       SeDuMi   1.34    {cvx}\sedumi
   1 solver skipped:
       GLPK             
           Could not find a GLPK installation.
   Saving updated preferences...done.
   Testing with a simple model...done!
   ---------------------------------------------------------------------------
   To change the default solver, type "cvx_solver <solver_name>".
   To save this change for future sessions, type "cvx_save_prefs".
   Please consult the users' guide for more information.
   ---------------------------------------------------------------------------
   

4. 现在您可以运行示例之一:

   >> cd('C:\cvx\examples')
   >> quickstart
   

如果您想连接到外部求解器(Gurobi 和 MOSEK)，请阅读 docs 中的相应部分。 。这需要 CVX Professional 许可证。