gradient from Eigen

partial_gradient.cpp

// test the partial derivative in one go

#include "adcpp.h"
#include <iostream>

using namespace adcpp;

static bwd::Double mysq(const bwd::Double &x, const bwd::Double &y) {
  return bwd::pow(x, 2) + bwd::pow(y, 3);
}

int main(const int argc, const char **argv) {
  //   bwd::Double x = bwd::Double(3.0);
  //   bwd::Double y = bwd::Double(2.0);
  //   bwd::Double f = mysq(x, y);

  //   bwd::Double::DerivativeMap derivative;
  //   f.derivative(derivative);

  //   std::cout << "result: " << f << std::endl
  //             << "x = " << x << std::endl
  //             << "y = " << y << std::endl
  //             << "fx = " << derivative(x) << std::endl
  //             << "fy = " << derivative(y) << std::endl;
  bwd::Matrix2d x;
  x << bwd::Double(1.0), bwd::Double(1.9), bwd::Double(1.5), bwd::Double(3.0);
  bwd::Vector2d c;
  c << bwd::Double(2.9), bwd::Double(4.8);

  bwd::Double y = (x * c).array().sum();

  Eigen::Vector2d fc;
  bwd::gradient(c, y, fc);
  std::cout << fc << std::endl;

  Eigen::Matrix2d fx;
  bwd::gradient(x, y, fx);
  std::cout << fx << std::endl;
}