Computes a scalar distance between the target (a set of desirable values for
the responses) and the responses values that have been either observed
or estimated for each point in the experimental space. Such
a distance is used to identify additional experimental points to be
investigated.
Usage
distance(xpop, xspace, yspace, weight, opt)
Arguments
xpop
A data frame containing the factor values for the experimental points
investigated; the row names uniquely identify each experimental
point (ID).
xspace
A data frame containing the factor values for the experimental points
defining the entire experimental region; the row names uniquely
identify each experimental point (ID).
yspace
A data frame containing the response values (either observed or
estimated) for the points in the experimental region.
weight
A numerical vector, of the same length as the number of responses,
containing the weights assigned to the each response; the sum
of the weights must be equal to 1.
opt
A character vector, of the same length as the number of responses,
defining if each response needs to be minimized or maximized.
The allowed values are 'mn' (minimize) and 'mx' (maximize).
Details
The function normalizes the response values with respect to the estimated limits of the response space,
so that the response values lie between 0 and 1. Subsequently, the function identifies the target
and computes a scalar distance between the target and the response values.
Value
fit
The scalar distances between the target and the response(s) values for the experimental points in
xpop.
obj.nn
Scalar distance from the target for the best experimental point identified by EMMA.
Author(s)
Laura Villanova, Kate Smith-Miles and Rob J Hyndman
References
Friedman J. H. (1991) 'Multivariate adaptive regression splines' (with
discussion), The Annals of Statistics 19, 1:141.
Villanova L., Falcaro P., Carta D., Poli I., Hyndman R., Smith-Miles K. (2010)
'Functionalization of Microarray Devices: Process Optimization Using a
Multiobjective PSO and Multiresponse MARS Modelling', IEEE CEC 2010,
DOI: 10.1109/CEC.2010.5586165