#NEWLINE# def _update_alpha( self , alpha ) : #NEWLINE# #INDENT# '\n        compute output array\n        ' #NEWLINE# if ( not self . _alpha ) : #NEWLINE# #INDENT# if ( alpha is None ) : #NEWLINE# #INDENT# alpha = 1.0 #NEWLINE# #UNINDENT# else : #NEWLINE# #INDENT# out [ : , 3 ] = alpha #NEWLINE# #UNINDENT# #UNINDENT# return alpha