No initialization (Like Eigen)

[strasdat]

No initialization (Like Eigen)

[strasdat]

Personally, I do not like c++/Eigen's philosophy to default to the efficient version, instead to the safe one:

int i;
std::cout << i << std::endl; // reading uninitialized value

In practice, there are only few cases where this is a performance bottleneck, and we really don't want to initialize the variable i.

In a perfect world

int i; // initializes to 0
int j [[uninitialized]]; // leaves j uninitialized

I can't change c++ built in types, but I can write libraries in such a way.

Long story short, I'd be okay to add a

static SE3<...> uninitilized();

factory which leaves the element uninitialized, if there is demand for it.

[ibtaylor]

Yeah, what I a mess. I thought this was sort of the reason for the new syntax int j{}; http://en.cppreference.com/w/cpp/language/value_initialization

I guess I was thinking about the situation where you have a std::vector of SE3d and want to resize() vs reserve()/push_back(). Afaik, you're forced to pass over and initialize all of the memory during the resize even if you plan on initializing with a loop after if your default constructor fully initializes.

[strasdat]

I'd say reserve()/push_back() is clearly the better approach in general, since you don't have to worry about how expensive the default constructor is for a type Foo.