Distributions Template Parameter Method

Distributions Template Parameter Method#

Method

Distributions

Math Description

uniform_method::standard uniform_method::accurate

uniform(s,d) uniform(i)

Standard method. uniform_method::standard_accurate supported for uniform(s, d) only.

gaussian_method::box_muller

gaussian

Generates normally distributed random number x thru the pair of uniformly distributed numbers u1 and u2 according to the formula: x=2lnu1sin(2πu2)

gaussian_method::box_muller2

gaussian lognormal

Generates normally distributed random numbers x1 and x2 thru the pair of uniformly distributed numbers u1 and u2 according to the formulas: x1=2lnu1sin2πu2 x2=2lnu1cos2πu2

gaussian_method::icdf

gaussian

Inverse cumulative distribution function (ICDF) method.

exponential_method::icdf exponential_method::icdf_accurate

exponential

Inverse cumulative distribution function (ICDF) method.

weibull_method::icdf weibull_method::icdf_accurate

weibull

Inverse cumulative distribution function (ICDF) method.

cauchy_method::icdf

cauchy

Inverse cumulative distribution function (ICDF) method.

rayleigh_method::icdf rayleigh_method::icdf_accurate

rayleigh

Inverse cumulative distribution function (ICDF) method.

bernoulli_method::icdf

bernoulli

Inverse cumulative distribution function (ICDF) method.

geometric_method::icdf

geometric

Inverse cumulative distribution function (ICDF) method.

gumbel_method::icdf

gumbel

Inverse cumulative distribution function (ICDF) method.

lognormal_method::icdf lognormal_method::icdf_accurate

lognormal

Inverse cumulative distribution function (ICDF) method.

lognormal_method::box_muller2 lognormal_method::box_muller2_accurate

lognormal

Generated normally distributed random numbers x1 and x2 by box_muller2 method are converted to lognormal distribution.

gamma_method::marsaglia gamma_method::marsaglia_accurate

gamma

For α>1, a gamma distributed random number is generated as a cube of properly scaled normal random number; for 0.6α<1, a gamma distributed random number is generated using rejection from Weibull distribution; for α<0.6, a gamma distributed random number is obtained using transformation of exponential power distribution; for α=1, gamma distribution is reduced to exponential distribution.

beta_method::cja beta_method::cja_accurate

beta

Cheng-Jonhnk-Atkinson method. For min(p,q)>1, Cheng method is used; for min(p,q)<1, Johnk method is used, if q+Kp2+C0(K=0.852...,C=0.956...) otherwise, Atkinson switching algorithm is used; for max(p,q)<1, method of Johnk is used; for min(p,q)<1,max(p,q)>1, Atkinson switching algorithm is used (CJA stands for Cheng, Johnk, Atkinson); for p=1 or q=1, inverse cumulative distribution function method is used; for p=1 and q=1, beta distribution is reduced to uniform distribution.

chi_square_method::gamma_based

chi_square

(most common): If ν17 or ν is odd and 5ν15, a chi-square distribution is reduced to a Gamma distribution with these parameters: Shape α=ν/2Offset a=0 Scale factor β=2 The random numbers of the Gamma distribution are generated.

binomial_method::btpe

binomial

Acceptance/rejection method for ntrialmin(p,1p)30 with decomposition into four regions: two parallelograms, triangle, left exponential tail, right exponential tail.

poisson_method::ptpe

poisson

Acceptance/rejection method for λ27 with decomposition into four regions: two parallelograms, triangle, left exponential tail, right exponential tail.

poisson_method::gaussian_icdf_based

poisson

for λ1, method based on Poisson inverse CDF approximation by Gaussian inverse CDF; for λ<1, table lookup method is used.

poisson_v_method::gaussian_icdf_based

poisson_v

for λ1, method based on Poisson inverse CDF approximation by Gaussian inverse CDF; for λ<1, table lookup method is used.

hypergeometric_method::h2pe

hypergeometric

Acceptance/rejection method for large mode of distribution with decomposition into three regions: rectangular, left exponential tail, right exponential tail.

negative_binomial_method::nbar

negative_binomial

Acceptance/rejection method for: (a1)(1p)p100 with decomposition into five regions: rectangular, 2 trapezoid, left exponential tail, right exponential tail.

multinomial_method::poisson_icdf_based

multinomial

Multinomial distribution with parameters m,k, and a probability vector p. Random numbers of the multinomial distribution are generated by Poisson Approximation method.

gaussian_mv_method::box_muller

gaussian_mv

BoxMuller method for gaussian_mv method.

gaussian_mv_method::box_muller2

gaussian_mv

BoxMuller2 method for gaussian_mv method.

gaussian_mv_method::icdf

gaussian_mv

Inverse cumulative distribution function (ICDF) method.

Parent topic: Host Distributions