code: def _apply_adj(self, a):
          # is projection the zero operator?
          if self.V.shape[1] == 0:
              return numpy.zeros(a.shape)
          '''Single application of the adjoint projection.'''
          c = inner(self.V, a, ip_B=self.ip_B)
          if self.Q is not None and self.R is not None:
              c = self.Q.dot(scipy.linalg.solve_triangular(self.R.T.conj(), c,
                                                           lower=True))
          return self.W.dot(cf _apply_adj(self, a):
          # is projection the zero operator?
          if self.V.shape[1] == 0:
              return numpy.zeros(a.shape)
          '''Single application of the adjoint projection.'''
          c = inner(self.V, a, ip_B=self.ip_B)
          if self.Q is not None and self.R is not None:
              c = self.Q.dot(scipy.linalg.solve_triangular(self.R.T.conj(), c,
                                                           lower=True))
          return self.W.dot(c)
docs: Single application of the adjoint projection.