| NFFT 3.5.0

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Solver - Inverse transforms

## Macros
#define | LANDWEBER (1U<< 0)
#define | STEEPEST_DESCENT (1U<< 1)
#define | CGNR (1U<< 2)
#define | CGNE (1U<< 3)
#define | NORMS_FOR_LANDWEBER (1U<< 4)
#define | PRECOMPUTE_WEIGHT (1U<< 5)
#define | PRECOMPUTE_DAMP (1U<< 6)

## Detailed Description

## Macro Definition Documentation

#define LANDWEBER (1U<< 0)

If this flag is set, the Landweber (Richardson) iteration is used to compute an inverse transform.

Author
  Stefan Kunis

Definition at line 784 of file nfft3.h.

Referenced by CONCAT().

#define STEEPEST_DESCENT (1U<< 1)

If this flag is set, the method of steepest descent (gradient) is used to compute an inverse transform.

Author
  Stefan Kunis

Definition at line 785 of file nfft3.h.

Referenced by CONCAT().

#define CGNR (1U<< 2)

If this flag is set, the conjugate gradient method for the normal equation of first kind is used to compute an inverse transform. Each iterate minimises the residual in the current Krylov subspace.

Author
  Stefan Kunis

Definition at line 786 of file nfft3.h.

Referenced by CONCAT(), inverse_linogram_fft(), inverse_mpolar_fft(), inverse_polar_fft(), inverse_radon_trafo(), main(), and reconstruct().

#define CGNE (1U<< 3)

If this flag is set, the conjugate gradient method for the normal equation of second kind is used to compute an inverse transform. Each iterate minimises the error in the current Krylov subspace.

Author
  Stefan Kunis

Definition at line 787 of file nfft3.h.

Referenced by CONCAT(), glacier(), and main().

#define NORMS_FOR_LANDWEBER (1U<< 4)

If this flag is set, the Landweber iteration updates the member dot_r_iter.

Author
  Stefan Kunis

Definition at line 788 of file nfft3.h.

Referenced by CONCAT(), solver_loop_one_step_landweber_complex(), and solver_loop_one_step_landweber_double().

#define PRECOMPUTE_WEIGHT (1U<< 5)

If this flag is set, the samples are weighted, eg to cope with varying sampling density.

Author
  Stefan Kunis

Definition at line 789 of file nfft3.h.

Referenced by CONCAT(), inverse_linogram_fft(), inverse_mpolar_fft(), inverse_polar_fft(), inverse_radon_trafo(), main(), reconstruct(), solver_loop_one_step_cgne_complex(), solver_loop_one_step_cgne_double(), solver_loop_one_step_cgnr_complex(), solver_loop_one_step_cgnr_double(), solver_loop_one_step_landweber_complex(), solver_loop_one_step_landweber_double(), solver_loop_one_step_steepest_descent_complex(), and solver_loop_one_step_steepest_descent_double().

#define PRECOMPUTE_DAMP (1U<< 6)

If this flag is set, the Fourier coefficients are damped, eg to favour fast decaying coefficients.

Author
  Stefan Kunis

Definition at line 790 of file nfft3.h.

Referenced by CONCAT(), glacier(), glacier_cv(), inverse_linogram_fft(), inverse_mpolar_fft(), inverse_polar_fft(), main(), reconstruct(), solver_loop_one_step_cgne_complex(), solver_loop_one_step_cgne_double(), solver_loop_one_step_cgnr_complex(), solver_loop_one_step_cgnr_double(), solver_loop_one_step_landweber_complex(), solver_loop_one_step_landweber_double(), solver_loop_one_step_steepest_descent_complex(), and solver_loop_one_step_steepest_descent_double().