1. A distribution evaluation apparatus comprising: an evaluation value calculating unit that calculates weighted energy as an evaluation value representing distribution of two located objects x and y, by calculating a product resulting from multiplying weighting function values ω(x) and ω(y) of a weighting function ω and probability density function values φ(x) and φ(y) of a probability density function φ representing densities or sizes of the two located objects x and y, by a mutual influence value determined by a function fr having as a variable a distance between the located objects x and y, and then by summing the resulting products with respect to all the located objects x and y into the weighted energy; and an evaluating unit that evaluates the distribution of the located objects in accordance with the evaluation value calculated by the evaluation value calculating unit.