  The soft-gluon approximation, which implies that radiated gluon carries away
a small fraction of initial parton's energy, is a commonly used assumption in
calculating radiative energy loss of high momentum partons traversing QGP
created at RHIC and LHC. While soft-gluon approximation is convenient,
different theoretical approaches reported significant radiative energy loss of
high $p_{\perp}$ partons, thereby questioning its validity. To address this
issue, we relaxed the soft-gluon approximation within DGLV formalism. The
obtained analytical expressions are quite distinct compared to the soft-gluon
case. However, numerical results for the first order in opacity fractional
energy loss lead to small differences in predictions for the two cases. The
difference in the predicted number of radiated gluons is also small. Moreover,
the effect on these two variables has an opposite sign, which when combined
results in almost overlapping suppression predictions. Therefore, our results
imply that, contrary to the commonly held doubts, the soft-gluon approximation
in practice works surprisingly well in DGLV formalism. Finally, we also discuss
generalizing this relaxation in the dynamical QCD medium, which suggests a more
general applicability of the conclusions obtained here.
