power_method

Contents

power_method#

mrinufft._utils.power_method(max_iter, operator, norm_func=None, x=None)[source]#

Power method to find the Lipschitz constant of an operator.

Parameters:
  • max_iter (int) – Maximum number of iterations

  • operator (FourierOperatorBase or child class) – NUFFT Operator of which to estimate the lipchitz constant.

  • norm_func (callable, optional) – Function to compute the norm , by default np.linalg.norm. Change this if you want custom norm, or for computing on GPU.

  • x (array_like, optional) – Initial value to use, by default a random numpy array is used.

Returns:

The lipschitz constant of the operator.

Return type:

float