NFFT 3.5.3alpha
Data Structures | Functions
NFCT - Nonequispaced fast cosine transform

Direct and fast computation of the discrete nonequispaced cosine transform. More...

Data Structures

struct  nfct_plan
 data structure for an NFCT (nonequispaced fast cosine transform) plan with double precision More...

Functions

void nfct_init_1d (nfct_plan *ths_plan, int N0, int M_total)
void nfct_init_2d (nfct_plan *ths_plan, int N0, int N1, int M_total)
void nfct_init_3d (nfct_plan *ths_plan, int N0, int N1, int N2, int M_total)
void nfct_init (nfct_plan *ths_plan, int d, int *N, int M_total)
void nfct_precompute_psi (nfct_plan *ths)
void nfct_trafo (nfct_plan *ths_plan)
void nfct_adjoint (nfct_plan *ths_plan)
void nfct_finalize (nfct_plan *ths_plan)

Detailed Description

Direct and fast computation of the discrete nonequispaced cosine transform.

Function Documentation

◆ nfct_init_1d()

void nfct_init_1d ( nfct_plan * ths_plan,
int N0,
int M_total )
extern

Creates a 1-dimensional transform plan.

  • ths_plan The plan for the transform
  • N0 The bandwidth $N$
  • M_total The number of nodes $x$
Author
Steffen Klatt

◆ nfct_init_2d()

void nfct_init_2d ( nfct_plan * ths_plan,
int N0,
int N1,
int M_total )
extern

Creates a 3-dimensional transform plan.

  • ths_plan The plan for the transform
  • N0 The bandwidth of dimension 1
  • N1 The bandwidth of dimension 2
  • M_total The number of nodes $x$
Author
Steffen Klatt

◆ nfct_init_3d()

void nfct_init_3d ( nfct_plan * ths_plan,
int N0,
int N1,
int N2,
int M_total )
extern

Creates a 3-dimensional transform plan.

  • ths_plan The plan for the transform
  • N0 The bandwidth of dimension 1
  • N1 The bandwidth of dimension 2
  • N2 The bandwidth of dimension 3
  • M_total The number of nodes $x$
Author
Steffen Klatt

◆ nfct_init()

void nfct_init ( nfct_plan * ths_plan,
int d,
int * N,
int M_total )
extern

Creates a d-dimensional transform plan.

  • ths_plan The plan for the transform
  • d the dimension
  • N The bandwidths
  • M_total The number of nodes $x$
Author
Steffen Klatt

◆ nfct_precompute_psi()

void nfct_precompute_psi ( nfct_plan * ths_plan)
extern

precomputes the values psi if the PRE_PSI is set the application program has to call this routine after setting the nodes this_plan->x

  • ths_plan The plan for the transform
Author
Steffen Klatt

◆ nfct_trafo()

void nfct_trafo ( nfct_plan * ths_plan)
extern

executes a NFCT (approximate,fast), computes for $j=0,...,M\_total-1$ $f_j^C(x_j) = \sum_{k \in I_0^{N,d}} \hat{f}_k^C * cos(2 \pi k x_j)$

  • ths_plan The plan for the transform
Author
Steffen Klatt

◆ nfct_adjoint()

void nfct_adjoint ( nfct_plan * ths_plan)
extern

executes a transposed NFCT (approximate,fast), computes for $k \in I_0^{N,d}$ $h^C(k) = \sum_{j \in I_0^{(M\_total,1)}} f_j^C * cos(2 \pi k x_j)$

  • ths_plan The plan for the transform
Author
Steffen Klatt

◆ nfct_finalize()

void nfct_finalize ( nfct_plan * ths_plan)
extern

Destroys a plan.

  • ths_plan The plan for the transform
Author
Steffen Klatt
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