Why options are not working in fracfract function?

I follow the instruction and the function fracfact is not working.

My code :

gen1 = fracfactgen('a b c d e f g h',7,8);
[a1,confounding] = fracfact(gen1,'X1',3);
size(a1)

Matlab Instructions :

[...] = FRACFACT(GEN, 'PARAM1',val1, 'PARAM2',val2,...) specifies one
%   or more of the following name/value pairs:
%
%       'MaxInt'      Maximum level of interaction to include in the
%                     confounding output (default 2)
%       'FactorNames' Cell array specifying the name for each factor
%                     (default names are X1, X2, ...)

I got the following error :

Error message :

Error using fracfact (line 51)
Invalid parameter name: X1.

Error in Bending_F_Factorial_design (line 67)
[a1,confounding] = fracfact(gen1,'X1',3);

Best regards.

Answer 1

[Geoff Hayes]

In the function signature and after the GEN input, each new input is a name/value pair - 'PARAM1',val1, 'PARAM2',val2, etc. The PARAMX is one of MaxInt or FactorNames. So one of these two parameter names must precede the value.

I think that all you need to do is change your function call from

 [a1,confounding] = fracfact(gen1,'X1',3);

to

 [a1,confounding] = fracfact(gen1,'FactorNames',{'X1'},'MaxInt',3);

Note how the X1 string is wrapped in {}. This is because the value expected for the FactorNames parameter is a cell array.

Try the above and see what happens!