pyDOE pbdesign not accepting large number of features

[Erik-van-der-Steen]

when I try n=60 I do get a return array
but for 61 or 64 I get an error
as if that isnt a 4-fold...
while it works for n=17 :-)

How to get a PB design for large numbers of uncertainties (>48 .. 500)?

Erik

AssertionError Traceback (most recent call last)
in
11 # # Plackett-Burman, by concept, ignoring Factors, then merge all PB designs over all concepts into one JS table
12 # PB_Design_Array = pbdesign(NrFeatures_Concept)
---> 13 PB_Design_Array = pbdesign(64)
14 print(f' PB_Design_Array:=<{PB_Design_Array}>\n PB_Design_Array.shape={PB_Design_Array.shape}')

~\AppData\Local\Programs\Python\Python37\lib\site-packages\pyDOE\doe_plackett_burman.py in pbdesign(n)
67 k = [idx for idx, val in enumerate(np.logical_and(f==0.5, e>0)) if val]
68
---> 69 assert isinstance(n, int) and k!=[], 'Invalid inputs. n must be a multiple of 4.'
70
71 k = k[0]

AssertionError: Invalid inputs. n must be a multiple of 4.