code: public static int cs_scatter(DZcs A, int j, double[] beta, int[] w, DZcsa x, int mark, DZcs C, int nz)
  	{
  		int i, p, Ap[], Ai[], Ci[] ;
  		DZcsa Ax = new DZcsa() ;
  		if (!CS_CSC(A) || (w == null) || !CS_CSC(C)) return (-1) ;	/* check inputs */
  		Ap = A.p ; Ai = A.i ; Ax.x = A.x ; Ci = C.i ;
  		for (p = Ap [j]; p < Ap [j+1] ; p++)
  		{
  			i = Ai [p] ;		/* A(i,j) is nonzero */
  			if (w [i] < mark)
  			{
  				w [i] = mark ;	/* i is new entry in column j */
  				Ci [nz++] = i ;	/* add i to pattern of C(:,j) */
  				if (x != null)
  					x.set(i, cs_cmult(beta, Ax.get(p))) ;  /* x(i) = beta*A(i,j) */
  			}
  			else if (x != null)
  			{
  				x.set(i, cs_cplus(x.get(i), cs_cmult(beta, Ax.get(p))));  /* i exists in C(:,j) already */
  			}
  		}
  		return (nz) ;
  	}
docs: Scatters and sums a sparse vector A(:,j) into a dense vector,
  x = x + beta * A(:,j).
  
  @param A
  the sparse vector is A(:,j)
  @param j
  the column of A to use
  @param beta
  scalar multiplied by A(:,j)
  @param w
  size m, node i is marked if w[i] = mark
  @param x
  size m, ignored if null
  @param mark
  mark value of w
  @param C
  pattern of x accumulated in C.i
  @param nz
  pattern of x placed in C starting at C.i[nz]
  @return new value of nz, -1 on error