Cassini                 package:clue                 R Documentation

_C_a_s_s_i_n_i _D_a_t_a

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

     A Cassini data set with 1000 points in 2-dimensional space which
     are drawn from the uniform distribution on 3 structures.  The two
     outer structures are banana-shaped; the "middle" structure in
     between them is a circle.

_U_s_a_g_e:

     data("Cassini")

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

     A classed list with components

     '_x': a matrix with 1000 rows and 2 columns giving the coordinates
          of the points.

     '_c_l_a_s_s_e_s': a factor indicating which structure the respective
          points belong to.

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

     Instances of Cassini data sets can be created using function
     'mlbench.cassini' in package 'mlbench'. The data set at hand was
     obtained using


         library("mlbench")
         set.seed(1234)
         Cassini <- mlbench.cassini(1000)


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

     data("Cassini")
     op <- par(mfcol = c(1, 2))
     ## Plot the data set:
     plot(Cassini$x, col = as.integer(Cassini$classes),
          xlab = "", ylab = "")
     ## Create a "random" k-means partition of the data:
     set.seed(1234)
     party <- kmeans(Cassini$x, 3)
     ## And plot that.
     plot(Cassini$x, col = cl_class_ids(party),
          xlab = "", ylab = "")
     ## (We can see the problem ...)
     par(op)

