Python Sparse data Analysis Package external MRI plugin.

Note

This page is a reference documentation. It only explains the class signature, and not how to use it. Please refer to the gallery for the big picture.

class mri.operators.gradient.base.GradBaseMRI(operator, trans_operator, shape, lips_calc_max_iter=10, lipschitz_cst=None, num_check_lips=10, verbose=0)[source]¶

Base Gradient class for all gradient operators Implements the gradient of following function with respect to x: .. math:: ||M x - y|| ^ 2

Parameters

data : np.ndarray

input data array. this is y

operator : function

a function that implements M

trans_operator : function

a function handle that implements M ^ T

shape : tuple

shape of observed data y

lipschitz_cst : int default None

The lipschitz constant for for given operator. If not specified this is calculated using PowerMethod

lips_calc_max_iter : int default 10

Number of iterations to calculate the lipschitz constant

num_check_lips : int default 10

Number of iterations to check if lipschitz constant is correct

verbose : int, default 0

verbosity for debug prints. when 1, prints if lipschitz constraints are satisfied