LSSTApplications  20.0.0
LSSTDataManagementBasePackage
polynomialUtils.cc
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1 // -*- LSST-C++ -*-
2 
3 /*
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24 
25 #include <mutex>
27 
28 namespace lsst {
29 namespace meas {
30 namespace astrom {
31 namespace detail {
32 
33 void computePowers(Eigen::VectorXd& r, double x) {
34  r[0] = 1.0;
35  for (int i = 1; i < r.size(); ++i) {
36  r[i] = r[i - 1] * x;
37  }
38 }
39 
40 Eigen::VectorXd computePowers(double x, int n) {
41  Eigen::VectorXd r(n + 1);
42  computePowers(r, x);
43  return r;
44 }
45 
46 void BinomialMatrix::extend(int const n) {
47  static std::mutex mutex;
48  auto& old = getMatrix();
49  int const m = old.rows() - 1;
50  if (n <= m) return;
51  Eigen::MatrixXd updated = Eigen::MatrixXd::Zero(n + 1, n + 1);
52  updated.topLeftCorner(old.rows(), old.cols()) = old;
53  for (int i = m + 1; i <= n; ++i) {
54  updated(i, 0) = 1.0;
55  updated(i, i) = 1.0;
56  for (int j = 1; j < i; ++j) {
57  updated(i, j) = updated(i - 1, j - 1) * (static_cast<double>(i) / static_cast<double>(j));
58  }
59  }
60  std::unique_lock<std::mutex> lock(mutex);
61  old.swap(updated);
62 }
63 
64 Eigen::MatrixXd& BinomialMatrix::getMatrix() {
65  static Eigen::MatrixXd it = Eigen::MatrixXd::Constant(2, 2, 1.0);
66  return it;
67 }
68 
69 } // namespace detail
70 } // namespace astrom
71 } // namespace meas
72 } // namespace lsst
polynomialUtils.h
x
double x
Definition: ChebyshevBoundedField.cc:277
std::unique_lock
STL class.
lsst
A base class for image defects.
Definition: imageAlgorithm.dox:1
lsst::meas::astrom::detail::computePowers
void computePowers(Eigen::VectorXd &r, double x)
Fill an array with integer powers of x, so .
Definition: polynomialUtils.cc:33
std::mutex
STL class.
m
int m
Definition: SpanSet.cc:49