Kirby2                package:NISTnls                R Documentation

_M_i_c_r_o_s_c_o_p_e _l_i_n_e _w_i_d_t_h _s_t_a_n_d_a_r_d_s

_D_e_s_c_r_i_p_t_i_o_n:

     The 'Kirby2' data frame has 151 rows and 2 columns of data from an
     NIST study on scanning electron microscope line width standards.

_F_o_r_m_a_t:

     This data frame contains the following columns:

     _y A numeric vector of response values.

     _x A numeric vector of input values.


_D_e_t_a_i_l_s:

     These data are the result of a NIST study involving scanning
     electron microscope line with standards.

_S_o_u_r_c_e:

     Kirby, R., NIST (197?).   Scanning electron microscope line width
     standards.

_E_x_a_m_p_l_e_s:

     Try <- function(expr) if (!inherits(val <- try(expr), "try-error")) val
     plot(y ~ x, data = Kirby2)
     Try(fm1 <- nls(y ~ (b1 + b2*x + b3*x**2) / (1 + b4*x + b5*x**2),
                data = Kirby2, trace = TRUE,
                start = c(b1 = 2, b2 = -0.1, b3 = 0.003,
                          b4 = -0.001, b5 = 0.00001)))
     Try(fm1a <- nls(y ~ (b1 + b2*x + b3*x**2) / (1 + b4*x + b5*x**2),
                data = Kirby2, trace = TRUE, alg = "port",
                start = c(b1 = 2, b2 = -0.1, b3 = 0.003,
                          b4 = -0.001, b5 = 0.00001)))
     Try(fm2 <- nls(y ~ (b1 + b2*x + b3*x**2) / (1 + b4*x + b5*x**2),
                data = Kirby2, trace = TRUE,
                start = c(b1 = 1.5, b2 = -0.15, b3 = 0.0025,
                          b4 = -0.0015, b5 = 0.00002)))
     Try(fm2a <- nls(y ~ (b1 + b2*x + b3*x**2) / (1 + b4*x + b5*x**2),
                  data = Kirby2, trace = TRUE, alg = "port",
                  start = c(b1 = 1.5, b2 = -0.15, b3 = 0.0025,
                            b4 = -0.0015, b5 = 0.00002)))
     Try(fm3 <- nls(y ~ cbind(1, x, x**2)/(1 + x*(b4 + b5*x)),
                data = Kirby2, trace = TRUE, algorithm = "plinear",
                start = c(b4 = -0.001, b5 = 0.00001)))
     Try(fm4 <- nls(y ~ cbind(1, x, x**2)/(1 + x*(b4 + b5*x)),
                data = Kirby2, trace = TRUE, algorithm = "plinear",
                start = c(b4 = -0.0015, b5 = 0.00002)))

