def BSR_Row_WriteScalar(A, i, x):
    """Write a scalar at each nonzero location in row i of BSR matrix A.

    Parameters
    ----------
    A : bsr_matrix
        Input matrix
    i : int
        Row number
    x : float
        Scalar to overwrite nonzeros of row i in A

    Returns
    -------
    A : bsr_matrix
        All nonzeros in row i of A have been overwritten with x.
        If x is a vector, the first length(x) nonzeros in row i
        of A have been overwritten with entries from x

    Examples
    --------
    >>> from numpy import array
    >>> from scipy.sparse import bsr_matrix
    >>> from pyamg.util.BSR_utils import BSR_Row_WriteScalar
    >>> indptr  = array([0,2,3,6])
    >>> indices = array([0,2,2,0,1,2])
    >>> data    = array([1,2,3,4,5,6]).repeat(4).reshape(6,2,2)
    >>> B = bsr_matrix( (data,indices,indptr), shape=(6,6) )
    >>> BSR_Row_WriteScalar(B,5,22)

    """
    blocksize = A.blocksize[0]
    BlockIndx = int(i / blocksize)
    rowstart = A.indptr[BlockIndx]
    rowend = A.indptr[BlockIndx + 1]
    localRowIndx = i % blocksize
    indys = A.data[rowstart:rowend, (localRowIndx), :].nonzero()
    A.data[rowstart:rowend, (localRowIndx), :][indys[0], indys[1]] = x
