Hi Tim, Thank you for your work on this useful library! I'm definitely interested in it. I have a question about the library. Are there linear-time functions to construct a heap from unordered data? AFAIK, at least for d-ary heaps, there exists a linear time construction algorithm (often called `build_heap`). In STL, there is `make_heap` function which has linear-time complexity. I think such construction functions are useful in some applications. And here are some comments on source codes and documentation: * Use of double underscores In heap/detail/tree_iterator.hpp, there are a few names that contain double underscores. But such names are reserved by compilers and should not be used. * Naming of functions of `increase` and `decrease` For min heap, the meaning of `increase` and `decrease` becomes ambiguous. Would it be nice to use ordinary `up_heap` and `down_heap` or something like that? * Coding style of nullary function signature In header files and documentation, nullary functions are written as return_type some_function(void) It is more C++'ish to write them as return_type some_function() * Readability of ampersands In the documentation (heap/xxxx_mutable.html), ampersands ('&') are used in the description of `update`, `increase` and `decrease`. I think it would be better to write 'and' instead of '&', since they are a bit ambiguous with reference symbols. Regards, Michel