How to convert from an AD<double> to a double ?

[abczhou123]

eg:
AD a=10;
double b=a;//error

[bradbell]

see
https://coin-or.github.io/CppAD/doc/value.htm

and
https://coin-or.github.io/CppAD/doc/var2par.htm

[abczhou123]

见 https://coin-or.github.io/CppAD/doc/value.htm

和 https://coin-or.github.io/CppAD/doc/var2par.htm

Thank you.

[bradbell]

I am converting this from issue 132 to a discussion