#ifndef STAN_MATH_PRIM_MAT_FUN_DIGAMMA_HPP
#define STAN_MATH_PRIM_MAT_FUN_DIGAMMA_HPP

#include <stan/math/prim/mat/vectorize/apply_scalar_unary.hpp>
#include <boost/math/special_functions/digamma.hpp>

namespace stan {
  namespace math {

    /**
     * Structure to wrap digamma() so it can be vectorized.
     * @param x Variable.
     * @tparam T Variable type.
     * @return Digamma function applied to x. 
     * @throw std::domain_error if x is a negative integer or 0
     */
    struct digamma_fun {
      template <typename T>
      static inline T fun(const T& x) {
        using boost::math::digamma;
        return digamma(x);
      }
    };

    /**
     * Vectorized version of digamma().
     * @param x Container.
     * @tparam T Container type.
     * @return Digamma function applied to each value in x. 
     * @throw std::domain_error if any value is a negative integer or 0
     */
    template <typename T>
    inline typename apply_scalar_unary<digamma_fun, T>::return_t
    digamma(const T& x) {
      return apply_scalar_unary<digamma_fun, T>::apply(x);
    }

  }
}

#endif
