text: #ifndef STAN_MATH_PRIM_SCAL_FUN_LOGICAL_OR_HPP
  #define STAN_MATH_PRIM_SCAL_FUN_LOGICAL_OR_HPP
  
  namespace stan {
    namespace math {
  
      /**
       * The logical or function which returns 1 if either
       * argument is unequal to zero and 0 otherwise.  Equivalent
       * to <code>x1 != 0 || x2 != 0</code>.
       *
         \f[
         \mbox{operator||}(x, y) =
         \begin{cases}
           0 & \mbox{if } x, y=0 \\
           1 & \mbox{if } x \neq 0 \textrm{ or } y\neq0\\[6pt]
           1 & \mbox{if } x = \textrm{NaN or } y = \textrm{NaN}
         \end{cases}
         \f]
       *
       * @tparam T1 Type of first argument.
       * @tparam T2 Type of second argument.
       * @param x1 First argument
       * @param x2 Second argument
       * @return <code>true</code> if either x1 or x2 is not equal to 0.
       */
      template <typename T1, typename T2>
      inline int
      logical_or(T1 x1, T2 x2) {
        return (x1 != 0) || (x2 != 0);
      }
  
    }
  }
  
  #endif
  