Xvert: This function creates an extreme vertices design in a...

In mixexp: Design and Analysis of Mixture Experiments

This function creates an extreme vertices design in a constrained mixture space.

Description

This function calls the function crvtave to create an extreme vertices design in a constrained mixture space. If there are only three factors the function DesignPoints is called to plot the results.

Usage

 
Xvert(nfac=3,uc=c(0,0),lc=c(0,0),nlc=0,lb=c(0,0),ub=c(0,0),coef,ndm=0,plot=TRUE,
                 cornerlabs = c("x1","x2","x3"), axislabs = c("x1","x2","x3"),
                 pseudo=TRUE)  

Arguments

nfac	an integer representing the number of mixture variables in the design. Maximum nfac=12
uc	a vector of length nfac containing upper constraints on each mixture component
lc	a vector of length nfac containing lower constraints on each mixture component
nlc	the number of linear constraints, the default is zero
lb	a vector of length nlc containing the lower bounds for the linear constraints
ub	a vector of length nlc containing the upper bounds for the linear constraints
coef	an nlc by nfac matrix containing the coefficients of the components of the linear constraints
ndm	an integer representing the highest order of centroids requested. An overall centroid is always included, 0 indicates no other centroids will be created, 1 indicates edge centroids are requested, etc.
plot	a logical variable indicating whether a plot of the design is desired when there are only 3 components. Default is TRUE
cornerlabs	This is a vector of text labels for the x1, x2 and x3 vertices. Use when there are only 3 components for plotting.
axislabs	This is a vector of text labels for the x1, x2 and x3 axis. Use when there are only 3 components for plotting.
pseudo	logical variable, when TRUE plot in pseudo component space when there are lower constraints.

Note

This function calls crvtave. If the number of factors is 3, the function DesignPoints is called to graph the results.

Author(s)

John S. Lawson [e-mail]

References

1. Piepel, G. F. "Programs for Generating Extreme Vertices and Centroids of Linearly Consrtained Experimental Regions" Journal of Quality Technology, Vol 20, No. 2, pp. 125-139, 1988.

2. "John Lawson, Cameron Willden (2016).", "Mixture Experiments in R Using mixexp.", "Journal of Statistical Software, Code Snippets, 72(2), 1-20.", "doi:10.18637/jss.v072.c02"

Examples

# Polvoron Example from Lawson
des<-Xvert(3,uc=c(.8,.95,.50),lc=c(0,.10,.05),ndm=1,plot=FALSE)


#Snee Marquardt(1976) example
Xvert(8,uc=c(.45,.50,.10,.4,.6,.2,.05,.05),lc=c(.1,.05,0,0,.1,.05,0,0),ndm=0)
    
# Example page 465
exvert<-Xvert(4,uc=c(.188,.128,.438,.438),lc=c(.124,.064,.374,.374),ndm=2)

# Example from Piepel 1988
coef<-matrix(c(.85,.9,1,.7,0,1),ncol=3,byrow=TRUE)
des<-Xvert(3,lc=c(.1,.1,0),uc=c(.5,.7,.7),nlc=2,lb=c(.9,.4),ub=c(.95,0),coef,ndm=1,plot=FALSE)

mixexp documentation built on Oct. 23, 2024, 9:06 a.m.