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
|
// ************************************************************************************************
//
// BornAgain: simulate and fit reflection and scattering
//
//! @file Device/Beam/Beam.cpp
//! @brief Implements class Beam.
//!
//! @homepage http://www.bornagainproject.org
//! @license GNU General Public License v3 or higher (see COPYING)
//! @copyright Forschungszentrum Jülich GmbH 2018
//! @authors Scientific Computing Group at MLZ (see CITATION, AUTHORS)
//
// ************************************************************************************************
#include "Device/Beam/Beam.h"
#include "Base/Spin/SpinMatrix.h"
#include "Base/Util/Assert.h"
#include "Base/Vector/GisasDirection.h"
#include "Device/Beam/IFootprint.h"
#include <numbers>
using std::numbers::pi;
//... Constructors, destructors:
Beam::Beam(double intensity, double wavelength, double alpha, double phi)
: m_intensity(intensity)
, m_wavelength(wavelength)
, m_alpha(alpha)
, m_phi(phi)
{
precompute();
}
Beam::~Beam() = default;
Beam* Beam::clone() const
{
auto* result = new Beam(m_intensity, m_wavelength, m_alpha, m_phi);
if (m_footprint)
result->m_footprint.reset(m_footprint->clone());
result->m_polarization = m_polarization;
return result;
}
//... Getters:
std::vector<const INode*> Beam::nodeChildren() const
{
if (m_footprint)
return {m_footprint.get()};
return {};
}
SpinMatrix Beam::polMatrix() const
{
return SpinMatrix::FromBlochVector(m_polarization);
}
//... Setters:
void Beam::setIntensity(double intensity)
{
m_intensity = intensity;
precompute();
}
void Beam::setWavelength(double wavelength)
{
if (wavelength <= 0)
throw std::runtime_error("Wavelength = " + std::to_string(wavelength)
+ " : wavelength must be set to positive value");
m_wavelength = wavelength;
precompute();
}
void Beam::setGrazingAngle(const double alpha)
{
m_alpha = alpha;
precompute();
}
void Beam::setAzimuthalAngle(double value)
{
m_phi = value;
precompute();
}
void Beam::setFootprint(const IFootprint* shape_factor)
{
m_footprint.reset(shape_factor ? shape_factor->clone() : nullptr);
}
//! Sets the polarization density matrix according to the given Bloch vector
void Beam::setPolarization(const R3& polarization)
{
if (polarization.mag() > 1.0)
throw std::runtime_error(
"Beam::setPolarization: "
"The given Bloch vector cannot represent a real physical ensemble");
m_polarization = polarization;
}
//... Private function:
//! To be called whenever wavelength or alpha or phi has changed.
void Beam::precompute()
{
ASSERT(m_intensity >= 0);
ASSERT(m_wavelength >= 0);
ASSERT(m_alpha >= 0);
m_wavenumber = (2 * pi) / m_wavelength;
m_k = vecOfKAlphaPhi(m_wavenumber, -m_alpha, -m_phi);
}
|
