www.gusucode.com > optimdemos 工具箱 matlab 源码程序 > optimdemos/runqpbox4prec.m
function [fval, exitflag, output, x] = runqpbox4prec %RUNQPBOX4PREC demonstrates 'HessMult' option for QUADPROG with bounds. % Documentation example. % Copyright 1984-2015 The MathWorks, Inc. problem = load('qpbox4'); % Get xstart, u, l, B, A, f xstart = problem.xstart; u = problem.u; l = problem.l; B = problem.B; A = problem.A; f = problem.f; mtxmpy = @qpbox4mult; % function handle to qpbox4mult nested function % Choose algorithm and the HessMult option options = optimoptions(@quadprog,'Algorithm','trust-region-reflective',... 'HessianMultiplyFcn',mtxmpy); % Pass B to qpbox4mult via the H argument. Also, B will be used in % computing a preconditioner for PCG. % A is passed as an additional argument after 'options' [x, fval, exitflag, output] = quadprog(B,f,[],[],[],[],l,u,xstart,options); function W = qpbox4mult(B,Y) %QPBOX4MULT Hessian matrix product with dense structured Hessian. % W = qpbox4mult(B,Y) computes W = (B + A*A')*Y where % INPUT: % B - sparse square matrix (512 by 512) % Y - vector (or matrix) to be multiplied by B + A'*A. % VARIABLES from outer function runqpbox4prec: % A - sparse matrix with 512 rows and 10 columns. % % OUTPUT: % W - The product (B + A*A')*Y. % % Order multiplies to avoid forming A*A', % which is large and dense W = B*Y + A*(A'*Y); end end