Gammad-class              package:distr              R Documentation

_C_l_a_s_s "_G_a_m_m_a_d"

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

     The Gammad distribution with parameters 'shape' = a, by default '=
     1', and 'scale' = s, by default '= 1', has  density

               d(x)= 1/(s^a Gamma(a)) x^(a-1) e^-(x/s)

     for x > 0, a > 0 and s > 0. The mean and variance are E(X) = a*s
     and Var(X) = a*s^2. C.f. 'rgamma'

_O_b_j_e_c_t_s _f_r_o_m _t_h_e _C_l_a_s_s:

     Objects can be created by calls of the form 'Gammad(scale,
     shape)'. This object is a gamma distribution.

_S_l_o_t_s:

     '_i_m_g': Object of class '"Reals"': The space of the image of this
          distribution has got dimension 1 and the name "Real Space". 

     '_p_a_r_a_m': Object of class '"GammaParameter"': the parameter of this
          distribution (scale and shape), declared at its instantiation 

     '_r': Object of class '"function"': generates random numbers (calls
          function rgamma)

     '_d': Object of class '"function"': density function (calls
          function dgamma)

     '_p': Object of class '"function"': cumulative function (calls
          function pgamma)

     '_q': Object of class '"function"': inverse of the cumulative
          function (calls function qgamma)

_E_x_t_e_n_d_s:

     Class '"AbscontDistribution"', directly.
      Class '"UnivariateDistribution"', by class
     '"AbscontDistribution"'.
      Class '"Distribution"', by class '"AbscontDistribution"'.

_M_e_t_h_o_d_s:

     _i_n_i_t_i_a_l_i_z_e 'signature(.Object = "Gammad")': initialize method 

     _s_c_a_l_e 'signature(object = "Gammad")': returns the slot 'scale' of
          the parameter of the distribution 

     _s_c_a_l_e<- 'signature(object = "Gammad")': modifies the slot 'scale'
          of the parameter of the distribution 

     _s_h_a_p_e 'signature(object = "Gammad")': returns the slot 'shape' of
          the parameter of the distribution 

     _s_h_a_p_e<- 'signature(object = "Gammad")': modifies the slot 'shape'
          of the parameter of the distribution 

_A_u_t_h_o_r(_s):

     Thomas Stabla Thomas.Stabla@uni-bayreuth.de,
      Florian Camphausen Florian.Camphausen@uni-bayreuth.de,
      Peter Ruckdeschel Peter.Ruckdeschel@uni-bayreuth.de,
      Matthias Kohl Matthias.Kohl@uni-bayreuth.de

_S_e_e _A_l_s_o:

     'GammaParameter-class' 'AbscontDistribution-class' 'Reals-class'
     'rgamma'

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

     G=Gammad(scale=1,shape=1) # G is a gamma distribution with scale=1 and shape=1.
     r(G)(1) # one random number generated from this distribution, e.g. 0.1304441
     d(G)(1) # Density of this distribution is 0.3678794 for x=1.
     p(G)(1) # Probability that x<1 is 0.6321206.
     q(G)(.1) # Probability that x<0.1053605 is 0.1.
     scale(G) # scale of this distribution is 1.
     scale(G)=2 # scale of this distribution is now 2.

