MIXSOFT Version 2.4.1 is a menu-driven collection of FORTRAN/77 subroutines and interactive routines useful in the design and analysis of mixture experiments and other constrained region experiments. Because constrained experimental regions involving mixture and/or non-mixture variables are regular- or irregularly-shaped polyhedrons, special methods are needed to design experiments for such experimental regions. MIXSOFT provides tools implementing these special methods needed for constrained region experimental design. MIXSOFT also contains limited capabilities for analyzing the data resulting from mixture experiments.
MIXSOFT capabilities include: (1) generating simplex-lattice and simplex-centroid designs, (2) entering and checking constraints on mixture components, (3) performing pseudocomponent transformations of mixture points, and (4) expanding points according to various mixture, mixture-amount, mixture-process variable, and nonmixture variable model forms. Routines are also provided for generating factorial, fractional factorial, and Plackett-Burman designs, and for forming mixture designs with process variables or a total-amount variable.
For mixture regions defined by lower and upper bounds on the components, there are capabilities for: (1) computing the number of extreme vertices, (2) generating the extreme vertices, (3) generating the center-of-mass or range-normalized-midrange centroids of various dimensional faces, and (4) generating mixture screening designs from classical two-level screening designs. For mixture regions defined by linear (in the components) inequality constraints, there are capabilities for generating the extreme vertices and averaged-extreme-vertices centroids of various dimensional faces. Optimal experimental design via the DETMAX algorithm provides for selecting designs from a candidate set of points (e.g., consisting of vertices and centroids) for mixture or non-mixture variable experiments.
Other capabilities include generating component effect endpoints and computing component effects (and their standard errors) along Orthogonal, Cox, or Piepel directions, and generating the data for forming component effects plots (also known as component response trace plots). Finally, a number of utility routines that support the other capabilities are provided. MIXSOFT does not currently have graphics or regression capabilities, since such capabilities are widely available in other software.
MIXSOFT is written in standard FORTRAN/77 and the source code is provided. Executable files for Pentium Pro (and equivalent or higher) PCs are also provided. MIXSOFT Version 2.4.1 was developed using the Lahey Fortran 95 compiler, and has been tested on several PCs under Windows 98, Windows 2002, Windows XP, and Windows Vista. Previous versions were tested on PCs with Microsoft 4.1 and 5.0 FORTRAN under DOS and earlier versions of Windows, on a VAX under VMS with VAX FORTRAN, and on SUN Sparcstations operating under UNIX. The software should run on any computer that has a FORTRAN/77 or higher compiler.
The 353-page MIXSOFT USER'S GUIDE contains code documentation, one or more examples of the use of each routine, and installation instructions. The large number of examples accounts for the length of the MIXSOFT USER'S GUIDE.
The available MIXSOFT and MIXSOFT USER'S GUIDE licenses are: "Single-User Computer" ($400), "Multi-User Computer" ($1000), and "Site" ($1200). The FORTRAN source codes, compile and link files, executable files for PCs, files associated with the MIXSOFT USER'S GUIDE examples, and a Portable Document File (PDF) version of the MIXSOFT USER’S GUIDE are provided on CD. Additional paper copies of the MIXSOFT USER'S GUIDE may be purchased for $45.