ADD: new track message, Entity class and Position class

libs/geographiclib/examples/example-DST.cpp

@@ -0,0 +1,62 @@
+// Example of using the GeographicLib::DST class
+
+#include <iostream>
+#include <exception>
+#include <vector>
+#include <GeographicLib/Math.hpp>
+#include <GeographicLib/DST.hpp>
+
+using namespace std;
+using namespace GeographicLib;
+
+class sawtooth {
+private:
+  double _a;
+public:
+  sawtooth(double a) : _a(a) {}
+  // only called for x in (0, pi/2].  DST assumes function is periodic, period
+  // 2*pi, is odd about 0, and is even about pi/2.
+  double operator()(double x) const { return _a * x; }
+};
+
+int main() {
+  try {
+    sawtooth f(Math::pi()/4);
+    DST dst;
+    int N = 5, K = 2*N;
+    vector<double> tx(N), txa(2*N);
+    dst.reset(N);
+    dst.transform(f, tx.data());
+    cout << "Transform of sawtooth based on " << N << " points\n"
+         << "approx 1, -1/9, 1/25, -1/49, ...\n";
+    for (int i = 0; i < min(K,N); ++i) {
+      int j = (2*i+1)*(2*i+1)*(1-((i&1)<<1));
+      cout << i << " " << tx[i] << " " << tx[i]*j << "\n";
+    }
+    tx.resize(2*N);
+    dst.refine(f, tx.data());
+    cout << "Add another " << N << " points\n";
+    for (int i = 0; i < min(K,2*N); ++i) {
+      int j = (2*i+1)*(2*i+1)*(1-((i&1)<<1));
+      cout << i << " " << tx[i] << " " << tx[i]*j << "\n";
+    }
+    dst.reset(2*N);
+    dst.transform(f, txa.data());
+    cout << "Retransform of sawtooth based on " << 2*N << " points\n";
+    for (int i = 0; i < min(K,2*N); ++i) {
+      int j = (2*i+1)*(2*i+1)*(1-((i&1)<<1));
+      cout << i << " " << txa[i] << " " << txa[i]*j << "\n";
+    }
+    cout << "Table of values and integral\n";
+    for (int i = 0; i <= K; ++i) {
+      double x = i*Math::pi()/(2*K), sinx = sin(x), cosx = cos(x);
+      cout << x << " " << f(x) << " "
+           << DST::eval(sinx, cosx, txa.data(), 2*N) << " "
+           << DST::integral(sinx, cosx, txa.data(), 2*N) << "\n";
+    }
+  }
+  catch (const exception& e) {
+    cerr << "Caught exception: " << e.what() << "\n";
+    return 1;
+  }
+}