octave: Quadratic Programming
25.2 Quadratic Programming
==========================
Octave can also solve Quadratic Programming problems, this is
min 0.5 x'*H*x + x'*q
subject to
A*x = b
lb <= x <= ub
A_lb <= A_in*x <= A_ub
-- : [X, OBJ, INFO, LAMBDA] = qp (X0, H)
-- : [X, OBJ, INFO, LAMBDA] = qp (X0, H, Q)
-- : [X, OBJ, INFO, LAMBDA] = qp (X0, H, Q, A, B)
-- : [X, OBJ, INFO, LAMBDA] = qp (X0, H, Q, A, B, LB, UB)
-- : [X, OBJ, INFO, LAMBDA] = qp (X0, H, Q, A, B, LB, UB, A_LB, A_IN,
A_UB)
-- : [X, OBJ, INFO, LAMBDA] = qp (..., OPTIONS)
Solve a quadratic program (QP).
Solve the quadratic program defined by
min 0.5 x'*H*x + x'*q
x
subject to
A*x = b
lb <= x <= ub
A_lb <= A_in*x <= A_ub
using a null-space active-set method.
Any bound (A, B, LB, UB, A_IN, A_LB, A_UB) may be set to the empty
matrix (‘[]’) if not present. The constraints A and A_IN are
matrices with each row representing a single constraint. The other
bounds are scalars or vectors depending on the number of
constraints. The algorithm is faster if the initial guess is
feasible.
OPTIONS
An optional structure containing the following parameter(s)
used to define the behavior of the solver. Missing elements
in the structure take on default values, so you only need to
set the elements that you wish to change from the default.
‘MaxIter (default: 200)’
Maximum number of iterations.
INFO
Structure containing run-time information about the algorithm.
The following fields are defined:
‘solveiter’
The number of iterations required to find the solution.
‘info’
An integer indicating the status of the solution.
0
The problem is feasible and convex. Global solution
found.
1
The problem is not convex. Local solution found.
2
The problem is not convex and unbounded.
3
Maximum number of iterations reached.
6
The problem is infeasible.
-- : X = pqpnonneg (C, D)
-- : X = pqpnonneg (C, D, X0)
-- : [X, MINVAL] = pqpnonneg (...)
-- : [X, MINVAL, EXITFLAG] = pqpnonneg (...)
-- : [X, MINVAL, EXITFLAG, OUTPUT] = pqpnonneg (...)
-- : [X, MINVAL, EXITFLAG, OUTPUT, LAMBDA] = pqpnonneg (...)
Minimize ‘1/2*x'*c*x + d'*x’ subject to ‘X >= 0’.
C and D must be real, and C must be symmetric and positive
definite.
X0 is an optional initial guess for X.
Outputs:
• minval
The minimum attained model value, 1/2*xmin’*c*xmin + d’*xmin
• exitflag
An indicator of convergence. 0 indicates that the iteration
count was exceeded, and therefore convergence was not reached;
>0 indicates that the algorithm converged. (The algorithm is
stable and will converge given enough iterations.)
• output
A structure with two fields:
• "algorithm": The algorithm used ("nnls")
• "iterations": The number of iterations taken.
• lambda
Not implemented.
DONTPRINTYET See also: optimset XREFoptimset, *notelsqnonneg:
DONTPRINTYET See also: optimset XREFoptimset, lsqnonneg
XREFlsqnonneg, qp XREFqp.