  We have undertaken a study of diluted magnetic semiconductors
$Ga_{1-x}Mn_{x}N$ and $Ga_{1-x}Cr_{x}N$ with $x=0.0625, 0.125$, using the all
electron linearized augmented plane wave method (LAPW) for different
configurations of Mn as well as Cr. We study four possible configurations of
the impurity in the wurtzite GaN structure to predict energetically most
favorable structure within the 32 atom supercell and conclude that the
near-neighbor configuration has the lowest energy. We have also analyzed the
ferro-magnetic as well as anti-ferromagnetic configurations of the impurity
atoms. The density of states as well as bandstructure indicate half metallic
state for all the systems. $T_c$ has also been estimated for the above systems.
