forward_as() [4/4]

template<typename T_desired , typename T_actual , require_all_eigen_t< T_desired, T_actual > * = nullptr, std::enable_if_t< !std::is_same< value_type_t< T_actual >, value_type_t< T_desired > >::value||!internal::eigen_static_size_match(T_desired::RowsAtCompileTime, std::decay_t< T_actual >::RowsAtCompileTime)||!internal::eigen_static_size_match(T_desired::ColsAtCompileTime, std::decay_t< T_actual >::ColsAtCompileTime)> * = nullptr>

T_desired stan::math::forward_as ( const T_actual &  a )

inline

Assume which type we get.

If actual type is not convertible to assumed type or in case of eigen types compile time rows and columns are not the same and desired sizes are not dynamic this has return type of T_desired, but it only throws. This version should only be used where it is optimized away so the throw should never happen.

This is intended to be used in compile time branches that would otherwise trigger compile error even though they are never executed.

Template Parameters

T_desired	type of output we need to avoid compile time errors
T_actual	actual type of the argument

Parameters

a	input value

Returns

nothing, this always throws

Exceptions

always

throws std::runtime_error

Definition at line 122 of file forward_as.hpp.