1stOpt - First Optimization. 1stOpt (the former name is Auto2Fit) is a robust, flexible and state-of-the-art optimization package. The unique optimization algorithm of UGO (Universal Global Optimization) makes the 1stOpt the best and the most efficient and effiective tool in the area of nonlinear regression worldwide today. 1stOpt is also easier, faster and powerful for solving linear, nonlinear and integer, mixed integer optimization modes, both constrained and unconstrained