$\newcommand{\W}[1]{ \; #1 \; } \newcommand{\R}[1]{ {\rm #1} } \newcommand{\B}[1]{ {\bf #1} } \newcommand{\D}[2]{ \frac{\partial #1}{\partial #2} } \newcommand{\DD}[3]{ \frac{\partial^2 #1}{\partial #2 \partial #3} } \newcommand{\Dpow}[2]{ \frac{\partial^{#1}}{\partial {#2}^{#1}} } \newcommand{\dpow}[2]{ \frac{ {\rm d}^{#1}}{{\rm d}\, {#2}^{#1}} }$
 # include <cppad/cppad.hpp> bool Value(void) { bool ok = true; using CppAD::AD; using CppAD::Value; // domain space vector size_t n = 2; CPPAD_TESTVECTOR(AD<double>) x(n); x[0] = 3.; x[1] = 4.; // check value before recording ok &= (Value(x[0]) == 3.); ok &= (Value(x[1]) == 4.); // declare independent variables and start tape recording CppAD::Independent(x); // range space vector size_t m = 1; CPPAD_TESTVECTOR(AD<double>) y(m); y[0] = - x[1]; // cannot call Value(x[j]) or Value(y[0]) here (currently variables) AD<double> p = 5.; // p is a parameter (does not depend on x) ok &= (Value(p) == 5.); // create f: x -> y and stop tape recording CppAD::ADFun<double> f(x, y); // can call Value(x[j]) or Value(y[0]) here (currently parameters) ok &= (Value(x[0]) == 3.); ok &= (Value(x[1]) == 4.); ok &= (Value(y[0]) == -4.); return ok; }