CODEWITHSUNDEEP
rcombinations
keerthana
keerthana

Reputation: 41

How can I find all possible combinations of vectors that multiply to a fixed product?

Suppose I have 3 vectors, L, Y, and R. How can I find all possible combinations of L, Y, and R that multiply to a given product?

For example, how can I find all the combinations of L, Y, and R such that L * Y * R = 6?

Upvotes: 4

Views: 74

Answers (2)

ThomasIsCoding
ThomasIsCoding

Reputation: 101343

Here is a brute-force base R solution using expand.grid + subset + Reduce

N <- 6
v <- seq(N)[N%%seq(N)==0]
res <- subset(
  res <- expand.grid(rep(list(v),3)),
  Reduce("*",res)==N
)

which gives

> res
   Var1 Var2 Var3
4     6    1    1
7     3    2    1
10    2    3    1
13    1    6    1
19    3    1    2
25    1    3    2
34    2    1    3
37    1    2    3
49    1    1    6

Upvotes: 1

Lennart Oelschl&#228;ger
Lennart Oelschl&#228;ger

Reputation: 518

What are possible values for your parameters? If not too many, brute-force is always an option:

L_space = seq(-10,10,0.1)
Y_space = seq(-10,10,0.1)
R_space = seq(-10,10,0.1)

for(L in L_space) for(Y in Y_space) for(R in R_space)
  if(L*Y*R==6) print(paste(L,Y,R))

Upvotes: 0

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