<< scidoe_lhsdesign Designs Models >>

Scidoe >> Scidoe > Designs > scidoe_star

scidoe_star

Produces a star point design of experiments

Calling Sequence

H = scidoe_star(nbvar)
[H, a] = scidoe_star(nbvar)
H = scidoe_star(nbvar,"Name",value)
[H, a] = scidoe_star(nbvar,"Name",value)

Parameters

nbvar :

a 1-by-1 matrix of doubles, positive integer, the number of variables of the experiments

Name :

a 1-by-1 matrix of strings. The options are "alpha" and "center".

value :

the value

H :

a 2*nbvar-by-nbvar matrix of doubles, the design of experiments

a :

a 1-by-1 matrix of doubles, a positive integer, the value of alpha

Description

This function computes a star points design of experiments, used as an additional block of runs in Response Surface Designs (RSM). Each factor is sequentially placed at +/-alpha, while all other factors are at zero. The value of alpha is determined by the user to give the design desirable properties.

The available options are the following.

A RSM design includes a factorial block of exeprimental runs and a block of center points. These points are used to calculate alpha, as follows0

If the design is "orthogonal",

alpha = sqrt(nbvar*(1+(nao/na))/(1+(nco/nc))),
where

If the design is rotatable,

alpha = nc^1/4,
where nc=2^nbvar are the factorial points.

If the design is "faced", then alpha=1.

The center points is a 1-by-2 row vector of doubles, positive integers, indicating the number of center points assigned in each block of the response surface design. The default number of center points is [1,1], meaning 1 center point in the factorial block of the doe and 1 center point in the star points block. Setting the number of center points is meaningful only for the "orthogonal" design.

Examples

// Star points placed on the face of a factorial design
H = scidoe_star(3)
H = scidoe_star(3,"alpha","faced")
// Star points block for orthogonal design with 3 factors
H = scidoe_star(3,"alpha","orthogonal")
// Star points block for rotatable design with 3 factors
H = scidoe_star(3,"alpha","rotatable")
// Star doe with 2 center points in the factorial block
// and 3 center points in the star points block
H = scidoe_star(3,"alpha","orthogonal","center",[2 3])

Bibliography

http://en.wikipedia.org/wiki/Central_composite_design

http://www.itl.nist.gov/div898/handbook/pri/section3/pri3361.htm

Authors


Report an issue
<< scidoe_lhsdesign Designs Models >>