Patent US 5,452,136

A reflecting mirror, wherein mirror segments are fused together thereby composing the reflecting mirror by formulating square sums of displacements at a plurality of sampling points on a mirror surface of the reflecting mirror as a function of a thermal expansion coefficient vector having components of deviations of thermal expansion coefficients of the respective mirror segments from the average thermal expansion coefficients of all the mirror segments, positions of the components corresponding to arranging positions of the respective mirror segments; generating a stochastic process wherein the smaller the square sum of the displacement of the thermal expansion coefficient vector, the larger the probability whereby the thermal expansion coefficient vector appears, by a computer using random numbers; selecting the thermal expansion coefficient vector minimizing the square sum of the displacement from the appeared thermal expansion coefficient vectors; and arranging and fusing together the mirror segments in accordance with the components thereof.