How much space is allocated by boost compressed_matrix? Is it true that it only allocates space for non-zero elements? If this is true, I don't understand why the following code gives bad_alloc error. namespace bubla = boost::numeric::ublas; typedef double value_type; typedef bubla::compressed_matrix<value_type> SparseMatrix; unsign...
I am confused on how the boost::compressed_matrix works. Suppose I declare the compressed_matrix like this: boost::numeric::ublas::compressed_matrix<double> T(1000, 1000, 3*1000); This allocates space for 3*1000 elements in a 1000x1000 matrix. Now how do I give it the locations which are the non-zero elements? When and how are the non...
We have a set of Documents , each has a set of Features. Given feature A, we need to know what is the probability of having feature B in the same document. I thought of building a probability matrix , s.t: M(i,j) = Probability of having feature B in a document , given that feature A is there. However , we have an additional requirem...
What's the best way to effectively remove a row from an ObjectMatrix2D? Use viewSelection to get all the other rows (is there a simpler way than me building arrays of rows and columns myself?) Transpose all the lower rows up one (docs mention transpose operation but I can't find any code for it) something else? If it matters I'm curr...
Is there any package to perform Sparse Linear Algebra computations, maybe based on fast and efficient C libraries? I searched on Hackage but I didn't find anything at regard: hmatrix, which uses GSL, BLAS and LAPACK, is great, but doesn't seem to include special algorithms to solve linear systems and eigen-values/vectors problems with sp...
I have a Perl script, which parses datafile and writes 5 output files filled with 1100 x 1300 grid. The script works, but in my opinion, it's clumsy and probably non-efficient. The script is also inherited code, which I have modified a little to make it more readable. Still, it's a mess. At the moment, the script reads the datafile(~4Mb...
I get strange behavior with respect to memory with Matlab and the cell2mat() function... what I would like to do is: cell_array_outer = cell(1,N) parfor k = 1:N cell_array_inner = cell(1,M); for i = 1:M A = do_some_math_and_return_a_sparse_matrix( ); cell_array_inner{i} = sparse(A); % do sparse() again just to be parano...