The type for tensor views.

create ?offset ?strides ?mask shape is a view over shape.

Defaults:

• offset defaults to 0.
• strides defaults to C-contiguous strides derived from shape.
• mask defaults to None (all indices valid).

Mask bounds are half-open intervals (start, end) per dimension.

If shape has a zero-size dimension, the resulting view has offset = 0 and no mask.

Warning. If explicit strides or mask lengths do not match Array.length shape, downstream array checks may raise Invalid_argument.

shape v is v's shape.

strides v is v's stride vector.

offset v is v's linear base offset.

ndim v is Array.length (shape v).

numel v is the product of dimensions in shape v.

numel of a scalar (ndim v = 0) is 1.

dim axis v is dimension axis of v.

Raises Invalid_argument if axis is outside [0; ndim v - 1].

stride axis v is stride axis of v.

Raises Invalid_argument if axis is outside [0; ndim v - 1].

mask v is v's optional validity mask.

A mask entry (b, e) means b <= index < e on the corresponding axis.

is_c_contiguous v is true iff v is recognized as C-contiguous.

strides_opt v is Some s if v can be represented as a standard strided view without partial masking, and None otherwise.

can_get_strides v is true iff strides_opt v is Some _.

is_materializable v is true iff can_get_strides v is true.

linear_index v idx is offset v + sum_i (idx.(i) * strides v.(i)).

Raises Invalid_argument if Array.length idx <> ndim v.

Note. This function does not validate index bounds or masks.

is_valid v idx is true iff idx is valid with respect to mask v.

If mask v = None, the result is true for any idx.

If mask v = Some m, idx must have the same rank and satisfy each masked interval bound.

reshape v new_shape returns a view over the same storage with new_shape when stride-compatible.

Supported cases include:

• C-contiguous reshape.
• Reshape by adding/removing singleton dimensions.
• Certain merge/split patterns on compatible strided layouts.
• All-zero-stride broadcast layouts.

Raises Invalid_argument if reshape cannot be represented, including size mismatches (except zero-size special cases), masked views, or incompatible stride patterns.

expand v new_shape broadcasts singleton dimensions to new_shape by setting corresponding strides to 0.

Scalars (ndim v = 0) may expand to any rank.

Raises Invalid_argument if ranks are incompatible for non-scalars, or if a non-singleton dimension would need expansion.

permute v axes reorders dimensions according to axes.

Raises Invalid_argument if axes is not a valid permutation of [0; ndim v - 1].

shrink v bounds restricts v to per-axis half-open intervals (start, end).

Bounds must satisfy 0 <= start < end <= size for each dimension.

Raises Invalid_argument if bounds are malformed or rank mismatches.

pad v padding adds virtual padding (before, after) per axis.

The resulting view keeps data in place and records valid original regions via a mask.

Raises Invalid_argument if:

• padding rank mismatches ndim v.
• A padding component is negative.

flip v axes_to_flip reverses selected axes by negating strides and shifting offset.

Raises Invalid_argument if axes_to_flip rank mismatches ndim v.