float coeff[21] = {
       3.8397063e-03,  5.8037312e-03,  1.0900080e-02,  1.9625409e-02,  
       3.1825740e-02,  4.6651198e-02,  6.2646408e-02,  7.7965012e-02,  
       9.0670823e-02,  9.9069264e-02,  1.0200526e-01,  9.9069264e-02,  
       9.0670823e-02,  7.7965012e-02,  6.2646408e-02,  4.6651198e-02,  
       3.1825740e-02,  1.9625409e-02,  1.0900080e-02,  5.8037312e-03,  
       3.8397063e-03 };