Dear J Forum,
I have an interesting problem for which I need more insights to proceed.
I have to determine three unknowns:
(a) W where 2 = $W = w1, w2
(b) L where 3 = $ L = l1 , l2 , l3
(c) F a dyad that takes scalar inputs
Such that
(6 1 5 2 3 4) -: \:; L F"0 0/ W NB. the order of values is known.
For example,
F =: *
(6 1 5 2 3 4) -: \:; L F"0 0/ W [W =. 3 9 [L =. 20 16 12
0
I designed a test that is essentially a blind brute force on the inputs
assuming F is given:
F =: 4 : 'x^2 - y^2' NB. for example
odometer =: #: i.@(*/)
test =: 3 : 0
n =. y
w =. odometer n,n
l =. odometer n,n,n
NB. I get a length error if I use bigger inputs. So chunking into 100's
for_i. i. 100 %~ {. $l do.
for_j. i. 100 %~ {. $w do.
b =. ('' -: I. (6 1 5 2 3 4) -:"1 1 (>@[ \:@,"_1@:(F"0 0/"1 1) >@])/
(_100{.(100*>:i){. l);(_100{.(100*>:j){. w))
smoutput i,j
if. b<1 do. break. [smoutput 'found it';i;j end.
end.
end.
''
)
I am not convinced that I can find a solution this way since the functional
forms are far too many to be tried out notwithstanding my other assumptions.
Any suggestions?
Regards,
Yuva
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