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LSST Data Management Base Package
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ReducedShear.cc
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1// -*- lsst-c++ -*-
2
3/*
4 * LSST Data Management System
5 * Copyright 2008, 2009, 2010 LSST Corporation.
6 *
7 * This product includes software developed by the
8 * LSST Project (http://www.lsst.org/).
9 *
10 * This program is free software: you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation, either version 3 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the LSST License Statement and
21 * the GNU General Public License along with this program. If not,
22 * see <http://www.lsstcorp.org/LegalNotices/>.
23 */
27
28namespace lsst {
29namespace afw {
30namespace geom {
31namespace 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
A logarithmic complex ellipticity with magnitude .
A complex ellipticity with magnitude .
Definition Distortion.h:44
ReducedShear & operator=(ReducedShear const &other)
Jacobian dAssign(ReducedShear const &other)
ReducedShear(std::complex< double > const &complex)
T sqrt(T... args)
T tanh(T... args)