is_same_v<> for is_same<>::value
decay_t<> for decay<>::type
is_integral_v<> for is_integral<>::value
invoke_result_t<> for invoke_result<>::type

std::result_of is deprecated as of c++17 and removed in c++20.

To access the solution values a dof tables are passed
too.

Fixes multiple copyright messages in the doxygen docu.

ag '\\file' -L --ignore=ThirdParty *Lib |xargs  sed -i 's/\(.*\)\\copyright/\1\\file\n\1\\copyright/'

The default ctor cannot be created anyway because of
constant members.

Remove the unused attribute _all_secondary_variables from SecondaryVariableCollection.

Clang format run on near-the-header lines.

Happy New Year