1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
/* Copyright 2019 David Grote, Maxence Thevenet, Remi Lehe
*
*
* This file is part of WarpX.
*
* License: BSD-3-Clause-LBNL
*/
#ifndef WARPX_SPECTRAL_K_SPACE_H_
#define WARPX_SPECTRAL_K_SPACE_H_
#include "SpectralKSpace_fwd.H"
#include "Utils/WarpX_Complex.H"
#include <AMReX_Array.H>
#include <AMReX_BoxArray.H>
#include <AMReX_Config.H>
#include <AMReX_GpuContainers.H>
#include <AMReX_LayoutData.H>
#include <AMReX_REAL.H>
#include <AMReX_RealVect.H>
#include <AMReX_Vector.H>
#include <AMReX_BaseFwd.H>
// `KVectorComponent` and `SpectralShiftFactor` hold one 1D array
// ("DeviceVector") for each box ("LayoutData"). The arrays are
// only allocated if the corresponding box is owned by the local MPI rank.
using RealKVector = amrex::Gpu::DeviceVector<amrex::Real>;
using KVectorComponent = amrex::LayoutData< RealKVector >;
using SpectralShiftFactor = amrex::LayoutData<
amrex::Gpu::DeviceVector<Complex> >;
// Indicate the type of correction "shift" factor to apply
// when the FFT is performed from/to a cell-centered grid in real space.
struct ShiftType {
enum{ TransformFromCellCentered=0, TransformToCellCentered=1 };
};
/**
* \brief Class that represents the spectral space.
*
* (Contains info about the size of the spectral space corresponding
* to each box in `realspace_ba`, as well as the value of the
* corresponding k coordinates)
*/
class SpectralKSpace
{
public:
amrex::BoxArray spectralspace_ba;
SpectralKSpace() : dx(amrex::RealVect::Zero) {}
SpectralKSpace( const amrex::BoxArray& realspace_ba,
const amrex::DistributionMapping& dm,
const amrex::RealVect realspace_dx );
KVectorComponent getKComponent(
const amrex::DistributionMapping& dm,
const amrex::BoxArray& realspace_ba,
const int i_dim, const bool only_positive_k ) const;
KVectorComponent getModifiedKComponent(
const amrex::DistributionMapping& dm, const int i_dim,
const int n_order, const bool nodal ) const;
SpectralShiftFactor getSpectralShiftFactor(
const amrex::DistributionMapping& dm, const int i_dim,
const int shift_type ) const;
protected:
amrex::Array<KVectorComponent, AMREX_SPACEDIM> k_vec;
// 3D: k_vec is an Array of 3 components, corresponding to kx, ky, kz
// 2D: k_vec is an Array of 2 components, corresponding to kx, kz
amrex::RealVect dx;
};
/**
* \brief Returns an array of coefficients (Fornberg coefficients), corresponding
* to the weight of each point in a finite-difference approximation of a derivative
* (up to order \c n_order).
*
* \param[in] n_order order of the finite-difference approximation
* \param[in] nodal whether the finite-difference approximation is computed
* on a nodal grid or a staggered grid
*/
amrex::Vector<amrex::Real>
getFornbergStencilCoefficients(const int n_order, const bool nodal);
#endif
|
