Arrays

So far we've only worked with relatively simple types, now it's time to look at the Array type. The first thing that makes this type more complex are its type parameters, the element type T and rank N, which have special handling compared to other type parameters in jlrs.

This special handling involves a single base type, ArrayBase<T, const N: isize>, and aliases for the four possible cases:

• Array == ArrayBase<Unknown, -1>
• TypedArray<T> == ArrayBase<T, -1>
• RankedArray<const N: isize> == ArrayBase<Unknown, N>
• TypedRankedArray<T, const N: isize> == ArrayBase<T, N>

As can be seen in this list it's possible to ignore the element type and rank of an array. A known element type must implement ConstructType, a known rank is greater than or equal to 0.

There are a few additional specialized type aliases:

• Vector == RankedArray<1>
• TypedVector<T> == TypedRankedArray<T, 1>
• VectorAny == TypedVector<Any>
• Matrix == RankedArray<2>
• TypedMatrix<T> == TypedRankedArray<T, 2>

The elements of Julia arrays are stored in column-major order, which is also known as "F" or "Fortran" order. The sequence 1, 2, 3, 4, 5, 6 maps to the following 2 x 3 matrix:

1  3  5
2  4  6

i.e.

[1 3 5; 2 4 6]