Solver is a class for computing the inverse NFFT iteratively.
The solver’s instantiation requires an initialized NFFT object used internally for the multiple forward and adjoint NFFT performed. The class uses conjugate-gradient as the default solver but alternative solvers may be specified at construct-time.
The solver must be first initialized by calling the before_loop() method.
The solver’s implementation let you carry one iteration at a time with a call to loop_one_step(). It is left to the user to chose whichever stopping condition to apply.
The class exposes the internals of the solver through its respective properties. For instance, the residuals for the current iteration can be accessed via the :attr:r_iter attribute.
Step size for search direction.
Initialize the solver internals.
Step size for search direction.
Weighted dotproduct of p_hat_iter.
Weighted dotproduct of r_iter.
Previous dot_r_iter.
Weighted dotproduct of v_iter.
Weighted dotproduct of z_hat_iter.
Previous dot_z_hat_iter.
The dtype of the solver.
Iterative solution.
The precomputation flags.
Perform one iteration of the solver.
Search direction.
Residual vector.
Residual vector update.
Weighting factors.
Damping factors.
Right hand side, samples.
Residual of normal equation of the first kind.