lsst.meas.astrom  14.0-7-g0d69b06+3
polynomialUtils.cc
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1 // -*- LSST-C++ -*-
2 
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24 
25 #include <mutex>
27 
28 namespace lsst { namespace meas { namespace astrom { namespace detail {
29 
30 void computePowers(Eigen::VectorXd & r, double x) {
31  r[0] = 1.0;
32  for (int i = 1; i < r.size(); ++i) {
33  r[i] = r[i - 1] * x;
34  }
35 }
36 
37 Eigen::VectorXd computePowers(double x, int n) {
38  Eigen::VectorXd r(n + 1);
39  computePowers(r, x);
40  return r;
41 }
42 
43 void BinomialMatrix::extend(int const n) {
44  static std::mutex mutex;
45  auto & old = getMatrix();
46  int const m = old.rows() - 1;
47  if (n <= m) return;
48  Eigen::MatrixXd updated = Eigen::MatrixXd::Zero(n + 1, n + 1);
49  updated.topLeftCorner(old.rows(), old.cols()) = old;
50  for (int i = m + 1; i <= n; ++i) {
51  updated(i, 0) = 1.0;
52  updated(i, i) = 1.0;
53  for (int j = 1; j < i; ++j) {
54  updated(i, j) = updated(i - 1, j - 1) *
55  (static_cast<double>(i) / static_cast<double>(j));
56  }
57  }
58  std::unique_lock<std::mutex> lock(mutex);
59  old.swap(updated);
60 }
61 
62 Eigen::MatrixXd & BinomialMatrix::getMatrix() {
63  static Eigen::MatrixXd it = Eigen::MatrixXd::Constant(2, 2, 1.0);
64  return it;
65 }
66 
67 }}}} // namespace lsst::meas::astrom::detail
m
void computePowers(Eigen::VectorXd &r, double x)
Fill an array with integer powers of x, so .