We have performed two kinds of non-linear fitting procedures to the single-particle energies in the sdgh major shell to obtain better shell model results. The low-lying energy eigenvalues of the light Sn isotopes with A = 103-110 in the sdgh-shell are calculated in the framework of the nuclear shell model by using CD-Bonn two-body effective nucleon-nucleon interaction. The obtained energy eigenvalues are fitted to the corresponding experimental values by using two different non-linear fitting procedures, i.e., downhill simplex method and clonal selection method. The unknown single-particle energies of the states 2s(1/2), 1d(3/2), and 0h(11/2) are used in the fitting methods to obtain better spectra of the Sn-104,Sn-106,Sn-108,Sn-110 isotopes. We compare the energy spectra of the Sn-104,Sn-106,Sn-108,Sn-110 and Sn-103,Sn-105,Sn-107,Sn-109 isotopes with/without a nonlinear fit to the experimental results.