I am trying to solve linear programming problem by R software . I have three files named A.txt, B.txt,F.txt . I have read this by the following code:
library( linprog )
Amat<-read.table("D:/Simplex/SimplexInitialTheoryWithRsoftware/src/A.txt",header=FALSE,sep=" ")
bvec<-read.table("D:/Simplex/SimplexInitialTheoryWithRsoftware/src/B.txt",header=FALSE,sep=" ")
cvec<-read.table("D:/Simplex/SimplexInitialTheoryWithRsoftware/src/F.txt",header=FALSE,sep=" ")
The link of the file is A.txt , B.txt , F.txt . I am trying to solve this problem by R software by the following code .
res <- solveLP( cvec, bvec, Amat, TRUE )
## print the results
print( res )
But I am getting the following error .
Error in solveLP(cvec, bvec, Amat, TRUE) :
Matrix A must have as many rows as constraints (=elements of vector b) and as many columns as variables (=elements of vector c).
But I have checked my file again and again . The dimension of A is 10*10 , dimension of B is 10*1 and dimension of F is 1*10 .
So why I am getting the error ?
Update : I have got an error after the following code .
cvec<-read.table("D:/Simplex/SimplexInitialTheoryWithRsoftware/src/F.txt",header=FALSE,sep=" ")
And the error is
Warning message:
In read.table("D:/Simplex/SimplexInitialTheoryWithRsoftware/src/F.txt", :
incomplete final line found by readTableHeader on 'D:/Simplex/SimplexInitialTheoryWithRsoftware/src/F.txt'
My assumption is that , the error is caused due to this line of code .
Based on Roland's comment, the error comes indeed from incorrect specification of the input objects. The code below is tried and tested:
library( linprog )
Amat<-as.matrix(read.table("C:\\Users\\ifragkos\\Documents\\Fun\\R\\A.txt",header=FALSE,sep=" "))
bvec<-c(read.table("C:\\Users\\ifragkos\\Documents\\Fun\\R\\B.txt",header=FALSE,sep=" "), recursive=T)
cvec<-c(read.table("C:\\Users\\ifragkos\\Documents\\Fun\\R\\F.txt",header=FALSE,sep=" "), recursive=T)
res<-solveLP(cvec, bvec, Amat, TRUE)
## print the results
print( res )
Result:
All Variables (including slack variables)
opt cvec min.c max.c marg marg.reg
V1 0.2374153 29.02 21.255258 73.654167 NA NA
V2 0.0000000 47.98 -Inf 79.114957 -31.13496 0.0672461
V3 0.0000000 -37.64 -Inf 53.342215 -90.98222 0.0751398
V4 0.0000000 -22.01 -Inf 95.534330 -117.54433 0.0529444
V5 0.0000000 -1.36 -Inf 45.246038 -46.60604 0.1159432
V6 0.0000000 4.72 -Inf 55.904385 -51.18439 0.0139935
V7 0.0000000 19.67 -Inf 122.901935 -103.23194 0.0450489
V8 0.0000000 24.32 -Inf 93.315656 -68.99566 0.0420672
V9 0.0000000 46.15 -Inf 57.745346 -11.59535 0.0444139
V10 0.0132743 48.21 18.994909 87.790333 NA NA
S V11 20.1358135 0.00 -0.497478 0.546882 0.00000 NA
S V12 24.2133223 0.00 -10.046381 0.432213 0.00000 NA
S V13 44.8115881 0.00 NA 0.155625 0.00000 NA
S V14 75.7667354 0.00 -1.509427 0.454518 0.00000 NA
S V15 1.3688361 0.00 -0.826885 0.312089 0.00000 NA
S V16 66.5207843 0.00 NA 0.123910 0.00000 NA
S V17 47.0617343 0.00 NA 0.181379 0.00000 NA
S V18 0.0000000 0.00 -Inf 0.456100 -0.45610 0.8502727
S V19 0.0000000 0.00 -Inf 1.084168 -1.08417 2.8651162
S V110 72.7149517 0.00 -0.919381 0.124553 0.00000 NA
Disclaimer:This is my first post in R, I am by no means an R expert. Based on the linprog API and @Roland's comment, I did a bit of tweaking of as.vector, looked up the examples of the linprog reference, and this SO post and came up with the above suggestion.
The reference of the c() function explains that recursive = TRUE "recursively descends through lists (and pairlists) combining all their elements into a vector." Omitting the recursion leads to the default recursive = FALSE, which results in the whole dataframe being returned as one element only:
# This one gives a proper vector
>bvec<-c(read.table("C:\\Users\\ifragkos\\Documents\\Fun\\R\\B.txt",
header=FALSE,sep=" "), recursive=T)
>bvec
V11 V12 V13 V14 V15 V16 V17 V18 V19 V110
28.60 34.69 63.04 84.67 12.78 85.24 61.21 7.50 3.79 93.81
# This gives one element only
>bvec<-c(read.table("C:\\Users\\ifragkos\\Documents\\Fun\\R\\B.txt",
header=FALSE,sep=" "))
>bvec
[1] 28.60 34.69 63.04 84.67 12.78 85.24 61.21 7.50 3.79 93.81
I hope this helps!
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