The perf cost is just too great for these to be enabled always. The only
place where the assertions are kept always is in the batch APIs -- there
it's assumed the function is called on large enough data to offset this
overhead, plus since it's often dealing with large blocks of data the
memory safety is more important than various FP drifts which were the
usual case why other assertions were firing.
This makes it possible to conveniently do things like
Containers::StridedArrayView1D<Float> array = …;
Vector4 vector{NoInit};
Utility::copy(array, vector); // or the other way around
which is especially useful together with the new JSON classes. In some
cases this means the function is no longer constexpr, but those weren't
constexpr because it was useful for anything, they were only because it
was possible. So this breakage shouldn't do any harm I think.
The old one is deprecated, and will be removed in a future release.
Unfortunately, to avoid deprecation warnings, all use of NoInit in the
Math library temporarily have to be Magnum::NoInit This will be cleaned
up when the deprecated alias is removed.
Now works both ways. The base class works with virtually any combination
that is supported by the underlying types, so e.g. Dual<Matrix3<T>>
could be multiplied/divided with Vector3<T> (result is Vector3<T>), with
Matrix3<T> (result is Matrix3<T>) or with T (result is Matrix3<T>).
The macros, on the other hand, because they are there only to help with
implementation of *my* subclasses, restrict that to the two only cases I
need (i.e. multiplication with Dual<T> and Dual<T::Type> and nothing
else). Could be extended in the future if it needs to be.
Useful for squeezing out last bits of performance, e.g. in this case:
Vector3 a;
a[0] = something++;
a[1] = something++;
a[2] = something++;
In the code all elements are first zeroed out and then overwritten
later, thus it might be good to avoid the zero-initialization:
Vector3 a{Math::NoInit};
a[0] = something++;
a[1] = something++;
a[2] = something++;
This will of course be more useful in far larger data types and arrays
of these.