<div>Hello,</div><div> </div><div>Maybe my question was too long.</div><div> </div><div>Can I use object 'big.matrix' and 'filebacked.big.matrix' in Rsymphony package?</div><div> </div><div>Is there any other way to use large matrices in Rsymphony, lets say 100.000 x 100.000 that take 50 GB of drive space? I don't know how else to work with large matrix if there is any other way to represent a large matrix with less space and I am a bit confused!! I am really new to such big data, because here I think I have already entered through the door of big data!</div>
<div> </div><div>Thanks a lot </div><div>Makro<br><br></div><div class="gmail_quote">On Wed, Jan 16, 2013 at 1:41 PM, Marko Limbek <span dir="ltr"><<a href="mailto:marko.limbek@gmail.com" target="_blank">marko.limbek@gmail.com</a>></span> wrote:<br>
<blockquote style="margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-color:rgb(204,204,204);border-left-width:1px;border-left-style:solid" class="gmail_quote"><div>Hello everyone</div><div> </div><div>I am turning to the list with my newest issue :)</div>
<div>I have been working on some ILP problem and I have reached the limit of 'matrix' function and within it 'dim' function, that allows me dimensions up to 10.000 x 10.000 or 15.000 x 15.000, but my current problem is 90.000 x 90.000 at least with my current constraints construction. And I might encounter problem of dimension 10^6 x 10^6. Than retreat and admit defeat? So I have been thinking about using package 'bigmatrix', but the problem is, that function 'Rsymphony_solve_LP' accepts 'matrix' in the place of 'mat' attribute and not 'filebacked.big.matrix'. Because it takes ncol(mat) and ncol(row) and object of type 'big.matrix' is list and it is quite complicated to reach actual dimensions:</div>
<div> </div><div>Easy access to dimensions:</div><div> </div><div>> A <- cbind(diag(1000), diag(1000), diag(1000), diag(1000))<br>> ncol(A)<br>[1] 4000</div><div> </div><div>Complicated access to dimensions:</div>
<div> </div><div>fbm <- filebacked.big.matrix(5000,5000, init=0, backingpath="path", backingfile="bm.txt", descriptorfile="descr.txt")</div><div>A1 <- cbind(fbm, fbm, fbm, fbm)</div>
<div>
> ncol(A1[1][[1]][,])<br>[1] 5000</div><div> </div><div>Plus that Rsymphony_solve_LP uses a internal function 'make_csc_matrix', which I can't find.</div><div>So I think that is quite complicated and I am looking for a way to use 'bigmatrix'. And also I have to make bigmatrix work and give me matrices of dimensions 10^5 x 10^5 and that I also haven't managed yet.</div>
<div> </div><div> </div><div>Before I have also tried to use only 'big.matrix' but it cannot even make a matrix of 20.000 x 20.000</div><div> </div><div>> BM <-big.matrix(20000,20000, init=0, type="integer")<br>
Error in big.matrix(20000, 20000, init = 0, type = "integer") : <br> Error: memory could not be allocated for instance of type big.matrix</div><div> </div><div>So, would it perhaps be possible for me to get a small piece of advice by anyone, whether I should continue solving that large problem in R?</div>
<div> </div><div> </div><div>Thank you a lot,</div><div> </div><div> </div><div>Marko</div><div> </div><div>PS: By the way, is it also possible that I ask someone about my constraints construction, because maybe it would be possible to reduce it?</div>
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