def tstd_dlldy(y, df):
 return ((((- (df + 1)) / (df - 2.0)) / (1 + ((y ** 2) / (df - 2.0)))) * y)

def tstd_dlldy ( y , df ) : return ( ( ( ( - ( df + 1 ) ) / ( df - 2.0 ) ) / ( 1 + ( ( y ** 2 ) / ( df - 2.0 ) ) ) ) * y )
derivative of log pdf of standardized t with respect to y parameters y : array_like data points of random variable at which loglike is evaluated df : array_like degrees of freedom .