Non-equispaced FFTs through the C interface of the FINUFFT library. More...

Detailed Description

Non-equispaced FFTs through the C interface of the FINUFFT library.

Data Types
type	finufft_t

Functions/Subroutines
subroutine, public	finufft_read_options (finufft, namespace)

subroutine, public	finufft_set_tolerance (finufft, tol)
	Set the requested tolerance directly, for callers that take it from an input variable of their own rather than from FINUFFTTolerance. More...

subroutine, public	finufft_init (finufft, finufft_options, N, dim, M, nthreads)

subroutine, public	finufft_precompute (finufft, X1, X2, X3, period)
	Hand the spatial nodes to FINUFFT. More...

subroutine, public	finufft_set_nodes (finufft, xj, yj, zj, period)
	Hand scattered nodes to FINUFFT, mapping one period of the mode grid onto the [-1/2, 1/2) of the transform. The nodes are counted by M(1), and the caller normalizes, so norm is left at one. More...

subroutine, public	finufft_modes_to_nodes (finufft, modes, values)
	Evaluate the Fourier modes on the scattered nodes. More...

subroutine, public	finufft_nodes_to_modes (finufft, values, modes)
	Project the scattered nodes onto the Fourier modes. More...

subroutine	finufft_scale_nodes (X, v, inv_spacing, period)
	Map the nodes onto [-1/2, 1/2) and return the reciprocal of the smallest scaled spacing. A positive period means the nodes already tile one period of that length, so they are only rescaled; otherwise they are stretched to fill the interval. More...

subroutine, public	finufft_write_info (finufft)

subroutine, public	finufft_end (finufft)

subroutine, public	dfinufft_forward (finufft, in, out)
	Evaluate the Fourier modes on the non-equispaced nodes. More...

subroutine, public	dfinufft_backward (finufft, in, out)
	Project the non-equispaced nodes back onto the Fourier modes. More...

subroutine, public	zfinufft_forward (finufft, in, out)
	Evaluate the Fourier modes on the non-equispaced nodes. More...

subroutine, public	zfinufft_backward (finufft, in, out)
	Project the non-equispaced nodes back onto the Fourier modes. More...

Function/Subroutine Documentation

◆ finufft_read_options()

subroutine, public finufft_oct_m::finufft_read_options	(	type(finufft_t), intent(inout)	finufft,
		type(namespace_t), intent(in)	namespace
	)

Definition at line 169 of file finufft.F90.

◆ finufft_set_tolerance()

subroutine, public finufft_oct_m::finufft_set_tolerance	(	type(finufft_t), intent(inout)	finufft,
		real(real64), intent(in)	tol
	)

Set the requested tolerance directly, for callers that take it from an input variable of their own rather than from FINUFFTTolerance.

Definition at line 195 of file finufft.F90.

◆ finufft_init()

subroutine, public finufft_oct_m::finufft_init	(	type(finufft_t), intent(inout)	finufft,
		type(finufft_t), intent(in)	finufft_options,
		integer, dimension(3), intent(in)	N,
		integer, intent(in)	dim,
		integer, dimension(3), intent(in)	M,
		integer, intent(in), optional	nthreads
	)

Parameters

[in]	n	number of Fourier modes
[in]	dim	number of spatial dimensions
[in]	m	number of spatial nodes
[in]	nthreads	number of threads

Definition at line 207 of file finufft.F90.

◆ finufft_precompute()

subroutine, public finufft_oct_m::finufft_precompute	(	type(finufft_t), intent(inout)	finufft,
		real(real64), dimension(:), intent(in), contiguous	X1,
		real(real64), dimension(:), intent(in), optional, contiguous	X2,
		real(real64), dimension(:), intent(in), optional, contiguous	X3,
		real(real64), dimension(:), intent(in), optional	period
	)

Hand the spatial nodes to FINUFFT.

Takes the 1D coordinate vectors defining each axis, X1 for x, X2 for y and X3 for z, and expands them into the Cartesian grid of nodes that FINUFFT expects as a flat list, indexed in Fortran order.

Parameters

[in] period Period of the node grid per direction, see finufft_scale_nodes

Definition at line 239 of file finufft.F90.

◆ finufft_set_nodes()

subroutine, public finufft_oct_m::finufft_set_nodes	(	type(finufft_t), intent(inout)	finufft,
		real(real64), dimension(:), intent(in), contiguous	xj,
		real(real64), dimension(:), intent(in), contiguous	yj,
		real(real64), dimension(:), intent(in), contiguous	zj,
		real(real64), dimension(:), intent(in), contiguous	period
	)

Hand scattered nodes to FINUFFT, mapping one period of the mode grid onto the [-1/2, 1/2) of the transform. The nodes are counted by M(1), and the caller normalizes, so norm is left at one.

Definition at line 323 of file finufft.F90.

◆ finufft_modes_to_nodes()

subroutine, public finufft_oct_m::finufft_modes_to_nodes	(	type(finufft_t), intent(in)	finufft,
		complex(real64), dimension(:,:,:), intent(in), contiguous	modes,
		complex(real64), dimension(:), intent(out), contiguous	values
	)

Evaluate the Fourier modes on the scattered nodes.

Definition at line 372 of file finufft.F90.

◆ finufft_nodes_to_modes()

subroutine, public finufft_oct_m::finufft_nodes_to_modes	(	type(finufft_t), intent(in)	finufft,
		complex(real64), dimension(:), intent(in), contiguous	values,
		complex(real64), dimension(:,:,:), intent(out), contiguous	modes
	)

Project the scattered nodes onto the Fourier modes.

Definition at line 399 of file finufft.F90.

◆ finufft_scale_nodes()

subroutine finufft_oct_m::finufft_scale_nodes	(	real(real64), dimension(:), intent(in), contiguous	X,
		real(real64), dimension(:), intent(out), contiguous	v,
		real(real64), intent(out)	inv_spacing,
		real(real64), intent(in)	period
	)

private

Map the nodes onto [-1/2, 1/2) and return the reciprocal of the smallest scaled spacing. A positive period means the nodes already tile one period of that length, so they are only rescaled; otherwise they are stretched to fill the interval.

Definition at line 429 of file finufft.F90.

◆ finufft_write_info()

subroutine, public finufft_oct_m::finufft_write_info ( type(finufft_t), intent(in) finufft )

Definition at line 461 of file finufft.F90.

◆ finufft_end()

subroutine, public finufft_oct_m::finufft_end ( type(finufft_t), intent(inout) finufft )

Definition at line 495 of file finufft.F90.

◆ dfinufft_forward()

subroutine, public finufft_oct_m::dfinufft_forward	(	type(finufft_t), intent(in)	finufft,
		real(real64), dimension(:,:,:), intent(in), contiguous	in,
		complex(real64), dimension(:,:,:), intent(out), contiguous	out
	)

Evaluate the Fourier modes on the non-equispaced nodes.

Definition at line 582 of file finufft.F90.

◆ dfinufft_backward()

subroutine, public finufft_oct_m::dfinufft_backward	(	type(finufft_t), intent(in)	finufft,
		complex(real64), dimension (:,:,:), intent(in), contiguous	in,
		real(real64), dimension(:,:,:), intent(out), contiguous	out
	)

Project the non-equispaced nodes back onto the Fourier modes.

Definition at line 601 of file finufft.F90.

◆ zfinufft_forward()

subroutine, public finufft_oct_m::zfinufft_forward	(	type(finufft_t), intent(in)	finufft,
		complex(real64), dimension(:,:,:), intent(in), contiguous	in,
		complex(real64), dimension(:,:,:), intent(out), contiguous	out
	)