...one of the most highly
regarded and expertly designed C++ library projects in the
world.

— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards

#include <boost/math/special_functions/gamma.hpp>

namespace boost{ namespace math{ template <class T1, class T2>calculated-result-typegamma_p_derivative(T1 a, T2 x); template <class T1, class T2, class Policy>calculated-result-typegamma_p_derivative(T1 a, T2 x, const Policy&); }} // namespaces

This function find some uses in statistical distributions: it implements
the partial derivative with respect to *x* of the incomplete
gamma function.

The final Policy argument is optional and can be used to control the behaviour of the function: how it handles errors, what level of precision to use etc. Refer to the policy documentation for more details.

Note that the derivative of the function gamma_q can be obtained by negating the result of this function.

The return type of this function is computed using the *result
type calculation rules* when T1 and T2 are different types,
otherwise the return type is simply T1.

Almost identical to the incomplete gamma function gamma_p: refer to the documentation for that function for more information.

This function just expose some of the internals of the incomplete gamma function gamma_p: refer to the documentation for that function for more information.