ImpactX
Multipole.H
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1 /* Copyright 2022-2023 The Regents of the University of California, through Lawrence
2  * Berkeley National Laboratory (subject to receipt of any required
3  * approvals from the U.S. Dept. of Energy). All rights reserved.
4  *
5  * This file is part of ImpactX.
6  *
7  * Authors: Chad Mitchell, Axel Huebl
8  * License: BSD-3-Clause-LBNL
9  */
10 #ifndef IMPACTX_MULTIPOLE_H
11 #define IMPACTX_MULTIPOLE_H
12 
14 #include "mixin/alignment.H"
15 #include "mixin/beamoptic.H"
16 #include "mixin/thin.H"
17 #include "mixin/nofinalize.H"
18 
19 #include <AMReX_Extension.H>
20 #include <AMReX_REAL.H>
21 #include <AMReX_GpuComplex.H>
22 
23 #include <cmath>
24 
25 namespace impactx
26 {
27  struct Multipole
28  : public elements::BeamOptic<Multipole>,
29  public elements::Thin,
30  public elements::Alignment,
32  {
33  static constexpr auto name = "Multipole";
35 
46  int multipole,
47  amrex::ParticleReal K_normal,
48  amrex::ParticleReal K_skew,
49  amrex::ParticleReal dx = 0,
50  amrex::ParticleReal dy = 0,
51  amrex::ParticleReal rotation_degree = 0
52  )
53  : Alignment(dx, dy, rotation_degree),
54  m_multipole(multipole), m_Kn(K_normal), m_Ks(K_skew)
55  {
56  // compute factorial of multipole index
57  int const m = m_multipole - 1;
58  m_mfactorial = 1;
59  for( int n = 1; n < m + 1; n = n + 1 ) {
60  m_mfactorial *= n;
61  }
62  }
63 
65  using BeamOptic::operator();
66 
78  PType& AMREX_RESTRICT p,
79  amrex::ParticleReal & AMREX_RESTRICT px,
80  amrex::ParticleReal & AMREX_RESTRICT py,
81  amrex::ParticleReal & AMREX_RESTRICT pt,
82  [[maybe_unused]] RefPart const & refpart) const {
83 
84  using namespace amrex::literals; // for _rt and _prt
85 
86  // shift due to alignment errors of the element
87  shift_in(p.pos(RealAoS::x), p.pos(RealAoS::y), px, py);
88 
89  // a complex type with two amrex::ParticleReal
91 
92  // access AoS data such as positions and cpu/id
93  amrex::ParticleReal const x = p.pos(RealAoS::x);
94  amrex::ParticleReal const y = p.pos(RealAoS::y);
95  amrex::ParticleReal const t = p.pos(RealAoS::t);
96 
97  // access reference particle values to find (beta*gamma)^2
98  //amrex::ParticleReal const pt_ref = refpart.pt;
99  //amrex::ParticleReal const betgam2 = pow(pt_ref, 2) - 1.0_prt;
100 
101  // intialize output values of momenta
102  amrex::ParticleReal pxout = px;
103  amrex::ParticleReal pyout = py;
104  amrex::ParticleReal ptout = pt;
105 
106  // assign complex position and complex multipole strength
107  Complex const zeta(x, y);
108  Complex const alpha(m_Kn, m_Ks);
109 
110  // compute complex momentum kick
111  int const m = m_multipole - 1;
112  Complex kick = amrex::pow(zeta, m);
113  kick *= alpha;
114  amrex::ParticleReal const dpx = -1.0_prt*kick.m_real/m_mfactorial;
115  amrex::ParticleReal const dpy = kick.m_imag/m_mfactorial;
116 
117  // advance position and momentum
118  p.pos(RealAoS::x) = x;
119  pxout = px + dpx;
120 
121  p.pos(RealAoS::y) = y;
122  pyout = py + dpy;
123 
124  p.pos(RealAoS::t) = t;
125  ptout = pt;
126 
127  // assign updated momenta
128  px = pxout;
129  py = pyout;
130  pt = ptout;
131 
132  // undo shift due to alignment errors of the element
133  shift_out(p.pos(RealAoS::x), p.pos(RealAoS::y), px, py);
134  }
135 
137  using Thin::operator();
138 
139  private:
142  amrex::ParticleReal m_Kn;
143  amrex::ParticleReal m_Ks;
144 
145  };
146 
147 } // namespace impactx
148 
149 #endif // IMPACTX_MULTIPOLE_H
#define AMREX_FORCE_INLINE
#define AMREX_GPU_HOST_DEVICE
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE GpuComplex< T > pow(const GpuComplex< T > &a_z, const T &a_y) noexcept
Definition: ImpactX.cpp:36
@ t
fixed t as the independent variable
int n
Definition: Multipole.H:32
amrex::ParticleReal m_Kn
factorial of multipole index
Definition: Multipole.H:142
int m_mfactorial
multipole index
Definition: Multipole.H:141
ImpactXParticleContainer::ParticleType PType
Definition: Multipole.H:34
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE void operator()(PType &AMREX_RESTRICT p, amrex::ParticleReal &AMREX_RESTRICT px, amrex::ParticleReal &AMREX_RESTRICT py, amrex::ParticleReal &AMREX_RESTRICT pt, [[maybe_unused]] RefPart const &refpart) const
Definition: Multipole.H:77
amrex::ParticleReal m_Ks
integrated normal multipole coefficient
Definition: Multipole.H:143
static constexpr auto name
Definition: Multipole.H:33
Multipole(int multipole, amrex::ParticleReal K_normal, amrex::ParticleReal K_skew, amrex::ParticleReal dx=0, amrex::ParticleReal dy=0, amrex::ParticleReal rotation_degree=0)
Definition: Multipole.H:45
int m_multipole
Definition: Multipole.H:140
@ x
position in x [m] (at fixed s OR fixed t)
Definition: ImpactXParticleContainer.H:48
@ y
position in y [m] (at fixed s OR fixed t)
Definition: ImpactXParticleContainer.H:49
@ t
c * time-of-flight [m] (at fixed s)
Definition: ImpactXParticleContainer.H:50
Definition: ReferenceParticle.H:30
Definition: alignment.H:27
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE void shift_out(amrex::ParticleReal &AMREX_RESTRICT x, amrex::ParticleReal &AMREX_RESTRICT y, amrex::ParticleReal &AMREX_RESTRICT px, amrex::ParticleReal &AMREX_RESTRICT py) const
Definition: alignment.H:91
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::ParticleReal dx() const
Definition: alignment.H:120
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE void shift_in(amrex::ParticleReal &AMREX_RESTRICT x, amrex::ParticleReal &AMREX_RESTRICT y, amrex::ParticleReal &AMREX_RESTRICT px, amrex::ParticleReal &AMREX_RESTRICT py) const
Definition: alignment.H:61
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::ParticleReal dy() const
Definition: alignment.H:130
Definition: beamoptic.H:135
Definition: nofinalize.H:22
Definition: thin.H:24