Examples
// Fractional factorial design, where the 3rd factors is the product of the first two H = scidoe_fracfact("a b ab") // The same with uppercase letters H = scidoe_fracfact("A B AB") // Use of operators H = scidoe_fracfact("a b -ab c +abc") |  |  |
Fractional Factorial Design
a 1-by-n matrix of strings, consisting of lowercase ,uppercase letters or operators "-" and "+", indicating the factors of the experiment
a m-by-n matrix of doubles, the fractional factorial design. m is 2^k, where k is the number of letters in gen, and n is the total number of entries in "gen"
The function computes a fractional factorial design. Fractional factorial designs are used instead of full factorial designs, because they need fewer runs.
In "gen" we define the main factors of the experiment and the factors whose levels are the products of the main factors. If gen = "a b ab", then "a" and "b" are the main factors, while the 3rd factor is the product of the first two. If we input uppecase letters in gen, we get the same result. We can also use the operators "+" and "-" in gen. If gen = "a b -ab", then the 3rd factor is the opposite of the product of "a" and "b".
The output matrix includes a two level full factorial design, built by the main factors of gen, and the products of the main factors. The columns of H follow the sequence of "gen". If gen = "a b ab c", then columns H(:,1), H(:,2) and H(4,:) include the two level full factorial design and H(:,3) includes the products of the main factors.
// Fractional factorial design, where the 3rd factors is the product of the first two H = scidoe_fracfact("a b ab") // The same with uppercase letters H = scidoe_fracfact("A B AB") // Use of operators H = scidoe_fracfact("a b -ab c +abc") | | |
http://www.itl.nist.gov/div898/handbook/pri/section3/pri3342.htm
http://www.mathworks.com/help/toolbox/stats/fracfact.html