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gradient.hpp
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1 #ifndef STAN_MATH_FWD_MAT_FUNCTOR_GRADIENT_HPP
2 #define STAN_MATH_FWD_MAT_FUNCTOR_GRADIENT_HPP
3
4 #include <stan/math/fwd/core.hpp>
5 #include <stan/math/prim/mat/fun/Eigen.hpp>
6
7 namespace stan {
8
9 namespace math {
10
11 using Eigen::Dynamic;
12
42 template <typename T, typename F>
43 void
44 gradient(const F& f,
45 const Eigen::Matrix<T, Dynamic, 1>& x,
46 T& fx,
47 Eigen::Matrix<T, Dynamic, 1>& grad_fx) {
48 Eigen::Matrix<fvar<T>, Dynamic, 1> x_fvar(x.size());
49 grad_fx.resize(x.size());
50 for (int i = 0; i < x.size(); ++i) {
51 for (int k = 0; k < x.size(); ++k)
52 x_fvar(k) = fvar<T>(x(k), k == i);
53 fvar<T> fx_fvar = f(x_fvar);
54 if (i == 0) fx = fx_fvar.val_;
55 grad_fx(i) = fx_fvar.d_;
56 }
57 }
58
59 } // namespace math
60 } // namespace stan
61 #endif
core.hpp
stan::math::fvar::d_
T d_
Definition: fvar.hpp:15
stan::math::fvar::val_
T val_
Definition: fvar.hpp:14
Eigen.hpp
stan::math::gradient
void gradient(const F &f, const Eigen::Matrix< T, Dynamic, 1 > &x, T &fx, Eigen::Matrix< T, Dynamic, 1 > &grad_fx)
Calculate the value and the gradient of the specified function at the specified argument.
Definition: gradient.hpp:44
stan::math::fvar
Definition: fvar.hpp:13

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