Bennett5               package:NISTnls               R Documentation

_M_a_g_e_n_t_i_z_a_t_i_o_n _m_o_d_e_l_l_i_n_g

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

     The 'Bennett5' data frame has 154 rows and 2 columns of data from
     a magnetism study

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

     This data frame contains the following columns:

     _y A numeric vector of magnetism values.

     _x A numeric vector of log(time).


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

     These data are the result of a NIST study involving
     superconductivity magnetization modeling.  The response variable
     is magnetism, and the predictor variable is the log of time in
     minutes.

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

     Bennett, L., L. Swartzendruber, and H. Brown,  NIST (1994).  
     Superconductivity Magnetization Modeling.

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

     Try <- function(expr) if (!inherits(val <- try(expr), "try-error")) val
     plot(y ~ x, data = Bennett5)
     Try(fm1 <- nls(y ~ b1*(b2+x)**(-1/b3), data = Bennett5,
                start = c(b1 = -2000, b2 = 50, b3 = 0.8), trace = TRUE))
     Try(fm1a <- nls(y ~ b1*(b2+x)**(-1/b3), data = Bennett5,
                 start = c(b1 = -2000, b2 = 50, b3 = 0.8),
                 trace = TRUE, alg = "port"))
     Try(fm2 <- nls(y ~ b1*(b2+x)**(-1/b3), data = Bennett5,
                start = c(b1 = -1500, b2 = 45, b3 = 0.85), trace = TRUE))
     Try(fm2a <- nls(y ~ b1*(b2+x)**(-1/b3), data = Bennett5,
                 start = c(b1 = -1500, b2 = 45, b3 = 0.85),
                 trace = TRUE, alg = "port"))
     Try(fm3 <- nls(y ~ (b2+x)**(-1/b3), data = Bennett5, alg = "plinear",
                start = c( b2 = 50, b3 = 0.8), trace = TRUE))
     Try(fm4 <- nls(y ~ (b2+x)**(-1/b3), data = Bennett5, alg = "plinear",
                start = c( b2 = 45, b3 = 0.8), trace = TRUE))

