Some problems unique to the construction of N-point D-optimal designs on convex design spaces are considered. Multiple-point augmentation and exchange algorithms are shown to be more costly and less efficient than the analogous single-point procedures. Moreover, some recommendations for improving single-point methods are given. Finally, empirical evidence is found that supports the Galil and Kiefer option for constructing initial designs and Powell's optimization method for design augmentation.
Bibliographical noteFunding Information:
The authors would like to thank the refereesa nd the editor for suggestionst hat led to a much improved presentation. The authors are also indebted to Dennis Cook for helpful comments during the course of their research,a nd to James Evans for help in implementing the modified simplex algorithm. This work was partially performed under the auspiceso f the United States Department of Energy (Contract w-7405- ENG.36).
- Conjugate directions
- Design augmentation
- Exchange algorithm
- Nonlinear optimization
- Simplex search