  Fitting the continuum component of a quasar spectrum in UV/optical band is
challenging due to contamination of numerous emission lines. Traditional
fitting algorithms such as the least-square fitting and the Levenberg-Marquardt
algorithm (LMA) are fast but are sensitive to initial values of fitting
parameters. They cannot guarantee to find global optimum solutions when the
object functions have multiple minima. In this work, we attempt to fit a
typical quasar spectrum using the Covariance Matrix Adaptation Evolution
Strategy (CMA-ES). The spectrum is generated by composing a number of real
quasar spectra from the Sloan Digital Sky Survey (SDSS) quasar catalog data
release 3 (DR3) so it has a higher signal-to-noise ratio. The CMA-ES algorithm
is an evolutionary algorithm that is designed to find the global rather than
the local minima. The algorithm we implemented achieves an improved fitting
result than the LMA and unlike the LMA, it is independent of initial parameter
values. We are looking forward to implementing this algorithm to real quasar
spectra in UV/optical band.
