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
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
|
/* Copyright 2019 Maxence Thevenet
*
* This file is part of WarpX.
*
* License: BSD-3-Clause-LBNL
*/
#ifndef SHAPEFACTORS_H_
#define SHAPEFACTORS_H_
/**
* Compute shape factor and return index of leftmost cell where
* particle writes.
* Specialized templates are defined below for orders 0 to 3.
*/
template <int depos_order>
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
int compute_shape_factor(amrex::Real* const sx, amrex::Real xint)
{
return 0;
};
/**
* Compute shape factor and return index of leftmost cell where
* particle writes.
* Specialization for order 0
*/
template <>
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
int compute_shape_factor <0> (amrex::Real* const sx, amrex::Real xmid){
using namespace amrex;
const auto j = static_cast<int>(xmid+0.5_rt);
sx[0] = 1.0_rt;
return j;
}
/**
* Compute shape factor and return index of leftmost cell where
* particle writes.
* Specialization for order 1
*/
template <>
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
int compute_shape_factor <1> (amrex::Real* const sx, amrex::Real xmid){
using namespace amrex;
const auto j = static_cast<int>(xmid);
const amrex::Real xint = xmid-j;
sx[0] = 1.0_rt - xint;
sx[1] = xint;
return j;
}
/**
* Compute shape factor and return index of leftmost cell where
* particle writes.
* Specialization for order 2
*/
template <>
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
int compute_shape_factor <2> (amrex::Real* const sx, amrex::Real xmid){
using namespace amrex;
const auto j = static_cast<int>(xmid+0.5_rt);
const amrex::Real xint = xmid-j;
sx[0] = 0.5_rt*(0.5_rt-xint)*(0.5_rt-xint);
sx[1] = 0.75_rt-xint*xint;
sx[2] = 0.5_rt*(0.5_rt+xint)*(0.5_rt+xint);
// index of the leftmost cell where particle deposits
return j-1;
}
/**
* Compute shape factor and return index of leftmost cell where
* particle writes.
* Specialization for order 3
*/
template <>
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
int compute_shape_factor <3> (amrex::Real* const sx, amrex::Real xmid){
using namespace amrex;
const auto j = static_cast<int>(xmid);
const amrex::Real xint = xmid-j;
sx[0] = 1.0_rt/6.0_rt*(1.0_rt-xint)*(1.0_rt-xint)*(1.0_rt-xint);
sx[1] = 2.0_rt/3.0_rt-xint*xint*(1.0_rt-xint/2.0_rt);
sx[2] = 2.0_rt/3.0_rt-(1.0_rt-xint)*(1.0_rt-xint)*(1.0_rt-0.5_rt*(1.0_rt-xint));
sx[3] = 1.0_rt/6.0_rt*xint*xint*xint;
// index of the leftmost cell where particle deposits
return j-1;
}
/**
* Compute shifted shape factor and return index of leftmost cell where
* particle writes, for Esirkepov algorithm.
* Specialized templates are defined below for orders 1, 2 and 3.
*/
template <int depos_order>
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
int compute_shifted_shape_factor (amrex::Real* const sx,
const amrex::Real x_old,
const int i_new);
/**
* Compute shifted shape factor and return index of leftmost cell where
* particle writes, for Esirkepov algorithm.
* Specialization for order 1
*/
template <>
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
int compute_shifted_shape_factor <1> (amrex::Real* const sx,
const amrex::Real x_old,
const int i_new){
using namespace amrex;
const auto i = static_cast<int>(x_old);
const int i_shift = i - i_new;
const amrex::Real xint = x_old - i;
sx[1+i_shift] = 1.0_rt - xint;
sx[2+i_shift] = xint;
return i;
}
/**
* Compute shifted shape factor and return index of leftmost cell where
* particle writes, for Esirkepov algorithm.
* Specialization for order 2
*/
template <>
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
int compute_shifted_shape_factor <2> (amrex::Real* const sx,
const amrex::Real x_old,
const int i_new){
using namespace amrex;
const auto i = static_cast<int>(x_old+0.5_rt);
const int i_shift = i - (i_new + 1);
const amrex::Real xint = x_old - i;
sx[1+i_shift] = 0.5_rt*(0.5_rt-xint)*(0.5_rt-xint);
sx[2+i_shift] = 0.75_rt-xint*xint;
sx[3+i_shift] = 0.5_rt*(0.5_rt+xint)*(0.5_rt+xint);
// index of the leftmost cell where particle deposits
return i-1;
}
/**
* Compute shifted shape factor and return index of leftmost cell where
* particle writes, for Esirkepov algorithm.
* Specialization for order 3
*/
template <>
AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
int compute_shifted_shape_factor <3> (amrex::Real* const sx,
const amrex::Real x_old,
const int i_new){
using namespace amrex;
const auto i = static_cast<int>(x_old);
const int i_shift = i - (i_new + 1);
const amrex::Real xint = x_old - i;
sx[1+i_shift] = 1.0_rt/6.0_rt*(1.0_rt-xint)*(1.0_rt-xint)*(1.0_rt-xint);
sx[2+i_shift] = 2.0_rt/3.0_rt-xint*xint*(1.0_rt-xint/2.0_rt);
sx[3+i_shift] = 2.0_rt/3.0_rt-(1.0_rt-xint)*(1.0_rt-xint)*(1.0_rt-0.5_rt*(1.0_rt-xint));
sx[4+i_shift] = 1.0_rt/6.0_rt*xint*xint*xint;
// index of the leftmost cell where particle deposits
return i-1;
}
#endif // SHAPEFACTORS_H_
|
