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cbsem (version 1.0.0)

FleishmanIC: Functions to generate nonnormal distributed multivariate random vectors with mean=0, var=1 and given correlations and coefficients of skewness and excess kurtosis. This is done with the method of Vale & Morelli: The coefficients of the Fleishman transform Y = -c + bX +cX^2 + dX^3 are computed. from given skewness gamma[1] = E(Y^3) and kurtosis gamma[2] = E(Y^4) - 3. A indermediate correlation matrix is computed from the desired correlation matrix and the Fleishman coefficients. A singular value decomposition of the indermediate correlation matrix is performed and a matrix of independend normal random numbers is generated and transformed into correlated ones. Finally the Fleishman transform is applied to the columns of this data matrix.

Description

The function are adapted from online support of the SAS system, URL: support.sas.com/publishing/authors/extras/65378_Appendix_D_Functions_for_Simulating_Data_by_Using_Fleishmans_Transformation.pdf FleishmanIC produce an initial guess of the Fleishman coefficients from given skewness and kurtosis. It is to use for Newton's algorithm. This guess is produced by a polynomial regression.

Usage

FleishmanIC(skew, kurt)

Arguments

skew

desired skewness

kurt

desired kurtosis

Value

par vector with coefficients b,c,d

Examples

Run this code
# NOT RUN {
out <- FleishmanIC(1,2)

# }

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