ffdesign2(basis), integer matrix basis containing confounding generators |

ffdesign2(basis) finds the set of factor/level combinations used in the 2^(k-p) fractional factorial corresponding to the given generators. The result is a CHARACTER vector giving the factor/level combinations. The p x k matrix basis contains the generators for the aliasing, one row for each generator and one column for each factor in the design. The elements in basis are 0, -1, or 1. A nonzero entry indicates that a factor is present in the generator for that row. The sign of a generator is the product of the signs of the nonzero elements of the generator. For example, 1 0 1 0 0 -1 means -ACF is a generator (alias of I). Examples: Cmd> print(b, format:"2.0f") # Matrix b is 2x5, so 2^(5-2) design b: (1,1) 1 1 1 0 0 [ABC is a generator] (2,1) 0 0 1 1 -1 [-CDE is a generator] Cmd> ffdesign2(b) (1) "ce" (2) "a" (3) "b" (4) "abce" (5) "dc" (6) "ade" (7) "bde" (8) "abdc"

Gary Oehlert 2003-01-15