Matrix

Matrix

Header: include/stratax/containers/Matrix.hpp.

stratax::container::Matrix<T> owns contiguous row-major elements of a supported DType, including bool. ArrayBase supplies storage, metadata, checked flat access, and iterators. Default construction produces empty shape {0, 0}.

Common interface and invariants

size() == shape().elements() and rank() == shape().rank() == strides().rank(). Metadata size/empty/rank/shape/strides queries take O(1). Shape and strides are read-only. operator[] is unchecked flat indexing; at(i) checks a signed flat index, including negative indices. Invalid at, front, or back access raises Exceptions::IndexError. data returns null for empty owning storage.

begin/end, const variants, and reverse iterators traverse flat row-major values; acquisition is O(1), traversal and fill are O(n). Owning iterators are contiguous. Member and ADL swap exchange storage and metadata in O(1). Pointers and iterators follow the allocation under its new owner; replacing or destroying storage invalidates its references. Slicing is a free function returning ArrayView.

Rank, construction, and moves

Rank stays two, including after a successful move. rows and cols query the two dimensions in O(1); strides are {cols(), 1}, including zero columns. Empty shapes {0, n} and {n, 0} are valid. Dimensions constructors value-initialize or fill elements. Shape construction requires rank two (ShapeError otherwise). Nested initializer lists must be rectangular (ShapeError otherwise); empty rows retain row count and zero columns.

operator(row, col) checks neither component. Both must be in range. at(row, col) checks signed components independently, including negatives, in O(1). Inherited one-argument at remains checked flat access.

Copies own independent storage and assignment has a strong exception guarantee. Moves transfer storage and leave a distinct source at {0, 0}. Empty metadata allocation may fail before transfer, so moves are not noexcept. Move construction is O(1); assignment also destroys old storage. Self-move is unchanged.

#include <stratax.h>
#include <cassert>
#include <utility>
 
int main() {
    stratax::container::Matrix<double> values{{1.0, 2.0}, {3.0, 4.0}};
    values(1, 0) = 8.0;
    assert(values.at(-1, 0) == 8.0);
    auto moved = std::move(values);
    assert(values.rows() == 0 && values.cols() == 0 && values.rank() == 2);
    assert(moved.at(-1) == 4.0);
}

Construction costs and failures

Allocation failures propagate. Shape/count/stride overflow raises DimensionError; byte-count overflow may raise std::bad_array_new_length. Construction copies or initializes n elements plus rank metadata. Matrix nested-list validation also visits each row, including empty rows. Invalid fixed-rank shapes are rejected by the container; see the generated header reference for exact constructors.

See ArrayBase, Shape, and ArrayView.