  The effect of symmetry energy and cross section had seen on the fragment
production in the multifragmentation of $^{20}Ne_{10}+ ^{20}Ne_{10}$ and
$^{197}Au_{79} + ^{197}Au_{79}$ at incident energy 50-1000 MeV/nucleon using
isospin dependent quantum molecular dynamics model. To see the effect of
symmetry energy and cross-section in more effective way relative yield of
$^{197}Au_{79}$ and $^{20}Ne_{10}$ was studied. It is observed that relative
yield of free nucleon, light mass fragment at isospin dependent cross-section
is almost same at different symmetry energy values. While for fixed
cross-section relative yield is influenced by symmetry energy. We compare the
stiffness of symmetry energy suggested by different groups with our value. To
verify our result we compare our study with ALADIN data.
