def cMultiplyScalar():
    """
    cMultiplyScalar subroutine.    
    """
    R = """
    KERNEL void cMultiplyScalar(
                 const float2 CA,
            GLOBAL_MEM float2 *CX)
    { 
    // Scale CX by CA: CX=CA*CX
    //  CA: scaling factor(float2)
    //*CX: input, output array(float2)
    int gid = get_global_id(0);  
    CX[gid].x=CA.x*CX[gid].x-CA.y*CX[gid].y;
    CX[gid].y=CA.x*CX[gid].y+CA.y*CX[gid].x;
    };           
    """
    return R
