docs for arb_mat_swap_rows

[Stephen Crowley]

documentation for arb_mat_swap_rows

.. function:: void arb_mat_swap_rows(arb_mat_t mat, slong* perm, slong r, slong s)

    Swaps two rows of a matrix.

    This function swaps the rows indexed by `r` and `s` in the matrix `mat`. If a permutation array `perm` is provided, it also records the swap in this array. The function is designed to be efficient and only performs the swap if `r` and `s` are different.

    :param arb_mat_t mat: The matrix in which rows are to be swapped.
    :param slong* perm: An optional permutation array. If non-NULL, the function records the swap in this array. The array should have at least as many elements as there are rows in the matrix.
    :param slong r: The index of the first row to swap.
    :param slong s: The index of the second row to swap.

    .. note::

        The indices `r` and `s` are zero-based, meaning that the first row of the matrix is indexed by 0.

    .. warning::

        The function assumes that the indices `r` and `s` are valid indices for rows of the matrix `mat`. Passing invalid indices may lead to undefined behavior.

    This function is part of the `arb` sublibrary of `flint`, which deals with matrix operations. It is typically used in algorithms that require row operations on matrices, such as Gaussian elimination or matrix inversion.