MATLAB: Full factorial design in MATLAB

factorial designff2nfracfactfull factorial designfullfactMATLAB

I am trying to generate a Full factorial design using the ff2n command. Is there a reason why the command generates a 2 level full factorial design with values of 0 and 1 for the 2 levels and not -1 and 1 ?

Because, in case of Fractional factorial design using fracfact command generates the design with values -1 and 1 for the levels.

Thank you in advance for your explanation.

Anurag Ramarao Murali.

Best Answer

"Because" is probably the best answer...the two levels are simply coded levels.

Related Solutions

MATLAB: How to create a fractional factorial design

Greetings,

I ran your code:

gen = fracfactgen('a b c d e f',4,4)  
[design, con] = fracfact(gen)

And, based on the output, I would say that you are not doing anything wrong, you are getting a fractional factoral design. First of all, if you have confounding, by definition, you are not running a full factorial experiment. Secondly, recall that full factorial designs have 2^k runs in them, where k is the number of factors. You have 6 factors in your design so a full factorial design would have 64 runs in it which translates to 64 rows in the design matrix.

The output of your code shows a design matrix with only 16 rows so you are definitely generating a fractional factorial design! It has been a long time since I studied design of experiments so I cant say much more than that without dusting off the ol' textbook.

Hope that helps~

MATLAB: Generating vectors of length N with only -1s and 1s.

>> M = 5;
>> N = 19;
>> randi(0:1,M,N)*2-1
ans =
  -1   1  -1   1  -1  -1   1  -1   1  -1  -1   1  -1   1   1  -1  -1   1   1
   1  -1  -1  -1  -1   1  -1  -1   1  -1  -1   1  -1  -1   1   1   1  -1   1
  -1   1  -1   1   1   1   1  -1   1  -1  -1  -1   1  -1   1   1   1   1  -1
   1  -1  -1   1  -1   1  -1  -1  -1  -1  -1   1  -1   1  -1   1   1   1  -1
  -1  -1   1  -1  -1  -1   1   1   1   1   1  -1  -1   1   1   1   1   1   1

Best Answer

Related Solutions

MATLAB: How to create a fractional factorial design

MATLAB: Generating vectors of length N with only -1s and 1s.

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