词条 | Fractional programming |
释义 |
In mathematical optimization, fractional programming is a generalization of linear-fractional programming. The objective function in a fractional program is a ratio of two functions that are in general nonlinear. The ratio to be optimized often describes some kind of efficiency of a system. DefinitionLet be real-valued functions defined on a set . Let . The nonlinear program where on , is called a fractional program. Concave fractional programsA fractional program in which f is nonnegative and concave, g is positive and convex, and S is a convex set is called a concave fractional program. If g is affine, f does not have to be restricted in sign. The linear fractional program is a special case of a concave fractional program where all functions are affine. PropertiesThe function is semistrictly quasiconcave on S. If f and g are differentiable, then q is pseudoconcave. In a linear fractional program, the objective function is pseudolinear. Transformation to a concave programBy the transformation , any concave fractional program can be transformed to the equivalent parameter-free concave program [1] If g is affine, the first constraint is changed to and the assumption that f is nonnegative may be dropped. DualityThe Lagrangian dual of the equivalent concave program is Notes1. ^{{cite journal|last1=Schaible |first1=Siegfried |title=Parameter-free Convex Equivalent and Dual Programs|journal=Zeitschrift für Operations Research |volume=18 |year=1974 |number=5 |pages=187–196|ref=harv|doi=10.1007/BF02026600|mr=351464}} References
1 : Optimization algorithms and methods |
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