Swift二进制运算符”不能应用于两个CGFloat操作数

func pointToCoordinate(position: CGPoint) -> (Int,int) {
        var gridHeight = 2 * singleRadius / sqrt(CGFloat(3)) * 1.5
        var gridWidth = 2 * singleRadius
        var halfWidth = singleRadius

        var relativePosition = CGPoint(x: position.x - @R_986_10586@lRadius / 2,y: position.y - @R_986_10586@lRadius / 2)
        println((relativePosition.y / gridHeight))
        var row = -(cgfloatToint)(relativePosition.y / gridHeight)
        var column: Int

        println((relativePosition.x + halfWidth * CGFloat(row + 1)) / (gridWidth))
        column = cgfloatToInt((relativePosition.x + halfWidth * CGFloat(row + 1)) / (gridWidth))

//        var innerY: CGFloat = CGFloat(relativePosition.y) + CGFloat(gridHeight * row)
        var innerX = relativePosition.x
        var innerY = relativePosition.y

        innerY = innerY - CGFloat(gridHeight * row)

        println((innerX,innerY))
        return (column,row)
    }