The QP solver in the OPTMODEL procedure implements an infeasible primal-dual predictor-corrector interior point algorithm that enables you to solve quadratic programming problems.
Mathematically, a quadratic programming problem can be stated as
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where
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is the quadratic (also known as Hessian) matrix |
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is the constraints matrix |
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is the vector of decision variables |
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is the vector of linear objective function coefficients |
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is the vector of constraints right-hand sides (RHS) |
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is the vector of lower bounds on the decision variables |
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is the vector of upper bounds on the decision variables |
The quadratic matrix
is assumed to be symmetric; that is,
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Indeed, even if
,
then the simple modification
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produces an equivalent formulation
hence symmetry is assumed. When you specify a quadratic matrix, it suffices to list only lower triangular coefficients.
In addition to being symmetric,
is also required to be positive semidefinite
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for minimization models; it is required to be negative semidefinite for maximization models. Convexity can come as a result of a matrix-matrix multiplication
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or as a consequence of physical laws, and so on.
For further details, see the SAS/OR® User's Guide: Mathematical Programming: The Quadratic Programming Solver.
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