Genetic Algorithm in R

Hi All, I am trying to implement Genetic Algorithm based on the 
request to fill 500 ask based on the inventory. Algorithm should
pick optimized combinations based on the rank (low rank inventory
should be selected first) and update the inventory after fulfilling
the request.

dataGA Inventory Rank 1        200    2 2        150    1 3 300
3 4        100    4 5         50    1 6        250    1 7 350    2
8        100    2 9        250    3 10        25    4 11 125    4
12       100    5 13       225    1 14       220    2 15 150    3

library(GA) Rastrigin <- function(x1, x2) { x1*x2 - 500 }

x1 <- dataGA$Inventory x2 <- seq(0.01, 1, by = 0.01)

f <- outer(x1, x2, Rastrigin) GA <- ga(type = "real-valued",
fitness = function(x) -Rastrigin(x1, x2), min = c(1000, 0.01), max
= c(10000000, 1), popSize = 50, maxiter = 100) summary(GA)I have 
solutions +-----------------------------------+ |         Genetic 
Algorithm         | +-----------------------------------+

GA settings: Type                  =  real-valued Population size =
50 Number of generations =  100 Elitism               =  2 
Crossover probability =  0.8 Mutation probability  =  0.1 Search 
domain x1   x2 Min  25 0.01 Max 350 1.00

GA results: Iterations             = 100 Fitness function value =
498 Solutions              = x1        x2 [1,]  194.44965 0.3886958
[2,] 191.24609 0.4016915 [3,]  243.08729 0.3699107 [4,]  137.36235 
0.4050092 [5,]  177.33917 0.4570788 [6,]  139.32841 0.3755744 [7,] 
137.68704 0.3534409 [8,]  156.28470 0.3825039 [9,]  196.84368 
0.4089103 [10,]  80.42056 0.3796008 ... [48,] 183.48574
0.4611285For the ask of 500, I want solutions to be
x1[c(2,5,6,13),] and x2[c(2,5,6,13),] with uniqueID which is a row
number here. Or please suggest any other Package/Algorithm
combination for this problem, Thank You,Best Regards,Chari