Terminology (and associated types)

[arteymix]

All this should probably end-up in the wiki.

Dimension

Number of independent axes.

• dimension is size_t as it defines the size of strides and shape

Axis

• ssize_t from the outside world for negative indexing
• size_t internally for indexing strides and shape
• plural form is axes

Index

• ssize_t[] to allow negative indexing
• length is implicitly given by the dimension
• computes a size_t offset using strides and shape

Offset

• size_t to index the raw memory

Strides

• ssize_t[] to allow negative indexing
• length is implicitly given by the dimension

Shape

• size_t[] as it define the length of each axes
• length is implicitly given by the dimension

Scalar

The scalar are the atoms of a dense array.

• scalar_size is a size_t
• scalar_type is a GType

Raw memory

• GBytes that wraps a uint8[] array

[arteymix]

Just to mention, all the size_t and ssize_t are refeering to gsize and gssize as described in https://developer.gnome.org/glib/stable/glib-Basic-Types.html They are alias with introspection.

[rainwoodman]

1.In general offset could be negative. I know it is impossible if it is GBytes. If it turns out necessary we can always flip.

1. in numpy, the argument newshape to reshape(newshape) is signed. If a newshape is [-1] it will be automatically inferred from the total size and the non -1 elements. Very handy feature. but it means sometimes shape can be ssize_t too.

Would it hurt if we make all offsets / shapes are ssize_t?

[arteymix]

I like to keep everything unsigned internally and signed externally to compute reverse offset/index.

We never really expose offsets, only via indexes which are already signed.

For reshape wouldn't it be nicer to fill smallest size first? Instead of having -1 for inferred dimension, we could have something like size_t.MAX for unconstrained axes.

arr.reshape ({2, 2, size_t.MAX}); // fill 2 by 2 and as much as possible in the last axis

[rainwoodman]

That's a great idea!

[arteymix]

I moved everything into the wiki: https://github.com/rainwoodman/vast/wiki/Types-and-Terminology

I will copy the comment about reshaping in #7.