A minimization procedure should stop when one of the following conditions is true:
The handling of these conditions is under user control. The functions below allow the user to test the precision of the current result.
GSL_SUCCESS
if the following condition is achieved,
|g| < epsabs
and returns GSL_CONTINUE
otherwise. A suitable choice of
epsabs can be made from the desired accuracy in the function for
small variations in x. The relationship between these quantities
is given by
\delta f = g \delta x.
GSL_SUCCESS
if the size is smaller than tolerance,
otherwise GSL_CONTINUE
is returned.