# desires-methods: Get and set methods In qualityTools: Statistical Methods for Quality Science

## Description

Set or get the desirability for each response of a factorial design. The desirability is stored in the facDesign object. Setting desirabilities is required for optimization of multiple responses.

## Usage

 ```1 2 3 4``` ```## S4 method for signature 'facDesign' desires(x) ## S4 replacement method for signature 'facDesign' desires(x) <- value ```

## Arguments

 `x` an object of class `facDesign` `value` an object of class `desirability`; see example

## Methods

`signature(objectc = "facDesign")`

Get and set the desires for an object of class `facDesign`.

## Author(s)

Thomas Roth [email protected]

## References

DERRINGER, G.; SUICH, R. 'Simulaneous Optimization of Several Response Variables', Journal of Quality Technology, vol. 12, no. 4. 214-219, 1980.

`desirability`
`fits`
`optimum`
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21``` ```#create a response surface design fdo = rsmDesign(k = 2, blocks = 2, alpha = "both") #set two responses for the response surface designs response(fdo) = data.frame(y= rnorm(14, 12, sd = 2), y2 = -2*fdo[,4]^2 - fdo[,5]^2 + rnorm(14, 12)) #set a fit for each response fits(fdo) = lm(y ~ A*B , data = fdo) fits(fdo) = lm(y2 ~ A*B + I(A^2) + I(B^2), data = fdo) #define a desirability for response y d = desirability(y, 6, 18, scale = c(0.5, 2), target = 12) #plot the desirability function plot(d) #set the desirability for y and y2 in the factorial design fdo desires(fdo) = d desires(fdo) = desirability(y2, 6, 18, scale = c(1, 1), target = "min") desires(fdo) ```