matrixGetLength0

matrixGetLength0 is a utility function used in matrix and tensor libraries to retrieve the size of the zero-th dimension of a given matrix or array. In 0-based indexing, this length corresponds to the number of rows in a two-dimensional matrix and to the size of the first axis in higher-dimensional tensors.

The function takes a single parameter, the matrix or tensor, and returns an integer representing the extent of dimension 0. If the input is a proper multi-dimensional array, the result is the length of its first axis. If the input is not an array, the function typically raises an error or throws an exception. Behavior for unusual inputs, such as scalars or jagged arrays, is specified by the library’s API and may vary.

Examples help illustrate its use. For a 3-by-4 matrix A, matrixGetLength0(A) yields 3. For a tensor with shape 1-by-5-by-2, it yields 1. The function may return 0 for an empty matrix that has zero rows. In some environments, extremely irregular structures or non-array inputs are rejected with a clear error message.

Implementation notes: in many languages, matrixGetLength0 is a thin wrapper around existing properties such as shape[0], size along axis 0, or the length of the first dimension. It is commonly contrasted with matrixGetLength1, which queries the second dimension. Always consult the specific library’s documentation for exact behavior and edge-case handling.

See also: matrixGetLength1, matrixGetLength, shape, rank.