LSSTApplications  20.0.0
LSSTDataManagementBasePackage
ReducedShear.cc
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1 // -*- lsst-c++ -*-
2 
3 /*
4  * LSST Data Management System
5  * Copyright 2008, 2009, 2010 LSST Corporation.
6  *
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8  * LSST Project (http://www.lsst.org/).
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27 
28 namespace lsst {
29 namespace afw {
30 namespace geom {
31 namespace ellipses {
32 
34  double e = getE();
35  return (1.0 - e) / (1.0 + e);
36 }
37 
39  double delta = other.getE();
40  if (delta < 1E-8) {
41  _complex = other.getComplex() * (0.5 + 0.125 * delta * delta);
42  } else {
43  double g = (1.0 - std::sqrt(1.0 - delta * delta)) / delta;
44  _complex = other.getComplex() * g / delta;
45  }
46  return *this;
47 }
48 
50  double eta = other.getE();
51  if (eta < 1E-8) {
52  _complex = other.getComplex() * (0.5 - eta * eta / 12.0);
53  } else {
54  double g = std::tanh(0.5 * eta);
55  _complex = other.getComplex() * g / eta;
56  }
57  return *this;
58 }
59 
61  Jacobian result = Jacobian::Zero();
62  double delta = other.getE();
63  double s = std::sqrt(1.0 - delta * delta);
64  double alpha, beta;
65  if (delta < 1E-8) {
66  alpha = 0.5 + 0.125 * delta * delta;
67  beta = 0.25;
68  } else {
69  alpha = (1.0 - s) / (delta * delta);
70  beta = (2.0 * alpha - 1.0) / (delta * delta * s);
71  }
72  _complex = other.getComplex() * alpha;
73  result(0, 0) = alpha + other.getE1() * other.getE1() * beta;
74  result(1, 1) = alpha + other.getE2() * other.getE2() * beta;
75  result(1, 0) = result(0, 1) = other.getE1() * other.getE2() * beta;
76  return result;
77 }
78 
80  Jacobian result = Jacobian::Zero();
81  double eta = other.getE();
82  double alpha, beta;
83  if (eta < 1E-8) {
84  alpha = 0.5 - eta * eta / 24.0;
85  beta = -1.0 / 12;
86  } else {
87  double g = std::tanh(0.5 * eta);
88  alpha = g / eta;
89  beta = (0.5 * (1.0 - g * g) - alpha) / (eta * eta);
90  }
91  _complex = other.getComplex() * alpha;
92  result(0, 0) = alpha + other.getE1() * other.getE1() * beta;
93  result(1, 1) = alpha + other.getE2() * other.getE2() * beta;
94  result(1, 0) = result(0, 1) = other.getE1() * other.getE2() * beta;
95  return result;
96 }
97 } // namespace ellipses
98 } // namespace geom
99 } // namespace afw
100 } // namespace lsst
ellipses
Distortion.h
lsst::afw
Definition: imageAlgorithm.dox:1
std::sqrt
T sqrt(T... args)
lsst::afw::geom::ellipses::ReducedShear::operator=
ReducedShear & operator=(ReducedShear const &other)
Definition: ReducedShear.h:60
lsst::afw::geom::ellipses::ConformalShear
A logarithmic complex ellipticity with magnitude .
Definition: ConformalShear.h:45
ConformalShear.h
lsst::afw::geom::ellipses::detail::EllipticityBase::Jacobian
Eigen::Matrix2d Jacobian
Definition: EllipticityBase.h:47
lsst::afw::geom::ellipses::ReducedShear::dAssign
Jacobian dAssign(ReducedShear const &other)
Definition: ReducedShear.h:71
other
ItemVariant const * other
Definition: Schema.cc:56
lsst::afw::geom::ellipses::detail::EllipticityBase::_complex
std::complex< double > _complex
Definition: EllipticityBase.h:91
lsst::afw::geom::ellipses::ReducedShear
A complex ellipticity with magnitude .
Definition: ReducedShear.h:45
result
py::object result
Definition: _schema.cc:429
lsst::afw::geom::ellipses::detail::EllipticityBase::getE
double getE() const
Definition: EllipticityBase.h:75
lsst
A base class for image defects.
Definition: imageAlgorithm.dox:1
lsst::afw::geom::ellipses::ReducedShear::getAxisRatio
double getAxisRatio() const
Definition: ReducedShear.cc:33
lsst::geom
Definition: geomOperators.dox:4
std::tanh
T tanh(T... args)
ReducedShear.h
lsst::afw::geom::ellipses::Distortion
A complex ellipticity with magnitude .
Definition: Distortion.h:44