#include <stan/math/fwd.hpp>
#include <gtest/gtest.h>
#include <boost/random/mersenne_twister.hpp>
#include <boost/math/distributions.hpp>

TEST(ProbDistributionsMultiStudentT, fvar_double) {
  using Eigen::Dynamic;
  using Eigen::Matrix;
  using stan::math::fvar;
  using stan::math::multi_student_t_lpdf;
  using std::vector;
  Matrix<fvar<double>, Dynamic, 1> y(3, 1);
  y << 2.0, -2.0, 11.0;
  Matrix<fvar<double>, Dynamic, 1> mu(3, 1);
  mu << 1.0, -1.0, 3.0;
  Matrix<fvar<double>, Dynamic, Dynamic> Sigma(3, 3);
  Sigma << 9.0, -3.0, 0.0, -3.0, 4.0, 0.0, 0.0, 0.0, 5.0;
  double nu = 4.0;

  for (int i = 0; i < 3; i++) {
    y(i).d_ = 1.0;
    mu(i).d_ = 1.0;
    for (int j = 0; j < 3; j++)
      Sigma(i, j).d_ = 1.0;
  }

  fvar<double> lp = multi_student_t_lpdf(y, nu, mu, Sigma);
  EXPECT_NEAR(-10.1246, lp.val_, 0.0001);
  EXPECT_NEAR(-0.0411685, lp.d_, 0.0001);
}

TEST(ProbDistributionsMultiStudentT, fvar_fvar_double) {
  using Eigen::Dynamic;
  using Eigen::Matrix;
  using stan::math::fvar;
  using stan::math::multi_student_t_lpdf;
  using std::vector;
  Matrix<fvar<fvar<double> >, Dynamic, 1> y(3, 1);
  y << 2.0, -2.0, 11.0;
  Matrix<fvar<fvar<double> >, Dynamic, 1> mu(3, 1);
  mu << 1.0, -1.0, 3.0;
  Matrix<fvar<fvar<double> >, Dynamic, Dynamic> Sigma(3, 3);
  Sigma << 9.0, -3.0, 0.0, -3.0, 4.0, 0.0, 0.0, 0.0, 5.0;
  double nu = 4.0;

  for (int i = 0; i < 3; i++) {
    y(i).d_.val_ = 1.0;
    mu(i).d_.val_ = 1.0;
    for (int j = 0; j < 3; j++)
      Sigma(i, j).d_.val_ = 1.0;
  }

  fvar<fvar<double> > lp = multi_student_t_lpdf(y, nu, mu, Sigma);
  EXPECT_NEAR(-10.1246, lp.val_.val_, 0.0001);
  EXPECT_NEAR(-0.0411685, lp.d_.val_, 0.0001);
}
