[R] Issue on LGP solving

Dr. Debasis Ghosh
Tue, 20 Sep 2016 06:12:16 -0000

I was solving a LGP problem which is very basic.



Find x0 = [x1; x2], n0 = [n1; n2; n3] and p0 = [p1; p2; p3] that minimize a
= [(2p1); (n2); (n3)]

The objectives are as follows

10x1 + 15x2 + n1 - p1 = 40

100x1 + 100x2 + n2 - p2 = 1000

x2 + n3 - p3 = 7

x; n; p >= 0

The solution is x' = [4; 0] and a = [0; 600; 7]





> local({pkg <- select.list(sort(.packages(all.available
TRUE)),graphics=TRUE)

+ if(nchar(pkg)) library(pkg, character.only=TRUE)})

> local({pkg <- select.list(sort(.packages(all.available
TRUE)),graphics=TRUE)

+ if(nchar(pkg)) library(pkg, character.only=TRUE)})





> coeff<-matrix (c(10,15,100,100,0,1), nrow=3, ncol=2, byrow=TRUE)

> target<-c(40,1000,7)

> p1<-c(2,0,0,0,0,0)

> p2 <- c(0,0,0,0,1,0)

> p3<- c(0,0,0,0,0,1)

> achievement <- data.frame(p1,p2,p3)

> achievement

  p1 p2 p3

1  2  0  0

2  0  0  0

3  0  0  0

4  0  0  0

5  0  1  0

6  0  0  1

> llgp(coeff,target,achievement)



Do you have any idea why I am seeing below error ?





Error in matrix(0, nrow = levels, ncol = nonbasics) :

  invalid 'nrow' value (too large or NA)

In addition: Warning messages:

1: In max(achievements$priority) :

  no non-missing arguments to max; returning -Inf

2: In matrix(0, nrow = levels, ncol = nonbasics) :

  NAs introduced by coercion to integer range



Regards,

Debasis Ghosh, Ph.D




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