How to use covariate factors for space filling design?
It is possible to use covariate factors with custom design, but not with space filling design.
In some case, it is preferable to screen homogeneously the design space.I tried to make a model with cubic, quartic terms to force the optimization to spread selected rows over the whole design space but the result could be better.
I also tried to use hierachical clustering using centroid criterion, then ...