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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 .

osimer pothe
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    The documentation (and even the parameter names) is very specific. The first two parameters must be vectors and the third a matrix. You are passing data.frames. – Roland Sep 18 '14 at 15:18

1 Answers1

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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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Ioannis
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  • Yes, I got that as well. Open `F.text`, place the cursor at the very end of line 1 and hit enter. Save the file, and the warning will go away. Also check [this](http://stackoverflow.com/questions/5990654/incomplete-final-line-warning-when-trying-to-read-a-csv-file-into-r) for more info. – Ioannis Sep 18 '14 at 17:37
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    Thanks for your kind help . It helps me a lot . The last word is , you are cordially invited for a treat . Contact with me if you ever visit Bangladesh . – osimer pothe Sep 25 '14 at 04:31
  • loannis , This package fails to solve lp problem when the rhs of constraint is negatiev . Why ? – osimer pothe Sep 28 '14 at 15:50
  • Did you check that the program you are trying to solve is actually feasible? If you do `[x,lambda,exitflag] = linprog(...)` then `exitflag` will [show the exit condition](https://nf.nci.org.au/facilities/software/Matlab/toolbox/optim/linprog.html). – Ioannis Sep 28 '14 at 17:50