code: def setcoef(self, Z):
          
  
          self.Z = np.asarray(Z, dtype=self.dtype)
          self.SZT = self.S.dot(Z.T)
          # Factorise dictionary for efficient solves
          self.lu, self.piv = sl.lu_factor(Z, self.rho)
          self.lu = np.asarray(self.lu, dtype=self.dtype)
docs: Set coefficient array.