I am using truncated SVD from scikit-learn package. In the definition of SVD, an original matrix A is approxmated as a product A ≈ UΣV* where U and V have orthonormal columns, and Σ is non-negativ...

/* The following codes are compiled into library(test.a) */ typedef struct { short x[5]; } weight_t; typedef struct { weight_t wgt; char *ptr; } tbl_t; /* huge static array and 70% of entries ...

For a current project I have to compute the inner product of a lot of vectors with the same matrix (which is quite sparse). The vectors are associated with a two dimensional grid so I store the vec...

I'm using sparse to construct, store, and read a large sparse matrix. I'd like to use Dask arrays to use its blocked algorithms features. Here's a simplified version of what I'm trying to do: fil...

I'm using Python Multiprocessing module to diagonalize a (large and sparse) matrix multiple times. I have to do this for a thousand times, so decided to do it in multiprocessing as I have 24 cores....

I am trying to create an identity matrix from a dataframe. The dataframe is like so: i<-c("South Korea", "South Korea", "France", "France","France&q...

I have a sparse matrix Formal class 'dgCMatrix' [package "Matrix"] with 6 slots ..@ i : int [1:37674] 1836 2297 108 472 1735 1899 2129 2131 5 67 ... ..@ p : int [1:3417] 0 2 8 22 25 35 44 45 45...

I used the Java's API, i.e. Apache-Spark 1.2.0, and created two parse vectors as follows. Vector v1 = Vectors.sparse(3, new int[]{0, 2}, new double[]{1.0, 3.0}); Vector v2 = Vectors.sparse(2, new ...

I am doing a text classification task with R, and I obtain a document-term matrix with size 22490 by 120,000 (only 4 million non-zero entries, less than 1% entries). Now I want to reduce the dimens...

I am working with a system that is using EF code first and I would like to use a number of SQL Server sparse columns on a table. My current solution is to drop the table created by EF and re-add vi...

For the base R matrix class we have the rowsum function, which is very fast for computing column sums across groups of rows. Is there an equivalent function or approach implemented in the Matrix-p...

I have built a small code that I want to use for solving eigenvalue problems involving large sparse matrices. It's working fine, all I want to do now is to set some elements in the sparse matrix to...

In Pandas, How can I check how sparse a DataFrame? Is there any function available, or I will need to write my own? For now, I have this: df = pd.DataFrame({'a':[1,0,1,1,3], 'b':[0,0,0,0,1], 'c':[4...

I have a sparse matrix in R I now wish to perform nonnegative matrix factorization on R data.txt is a text file i created using python, it consists of 3 columns where first column specifies the row...

I have a scipy.sparse.csr matrix and would like to dump it to a CSV file. Is there a way to preserve the sparsity of the matrix and write it to a CSV?

Using Scikit-learn (v 0.15.2) for non-negative matrix factorization on a large sparse matrix (less than 1% values > 0). I want to find factors by minimizing errors only on non-zero values of the ma...

In my Python application, I find it handy to use a dictionary of dictionaries as the source data for constructing a sparse pandas DataFrame, which I then use to train a model in sklearn. The struc...

I am working with a 19089 x 9432 sparse Matrix of class "dgCMatrix" (let's call it M), and I have to extract each row to perform some calculations on it. I do this with a loop, so at each...

Graphs are very useful for modeling real-world phenomena and relationships. Broadly, graph data structures and algorithms are divided into two categories: Those useful for sparse graphs (e.g. adja...

Hi all I have a csv file which contains data as the format below A a A b B f B g B e B h C d C e C f The first column contains items second column contains available feature from feature vector=...

I am trying to implement ALS algorithm in Dask, but I am having trouble figuring out how to compute latent feautures in one step. I followed formulas on this stackoverflow thread and come up with t...

I have been trying to divide a python scipy sparse matrix by a vector sum of its rows. Here is my code sparse_mat = bsr_matrix((l_data, (l_row, l_col)), dtype=float) sparse_mat = sparse_mat / (sp...

I have a question about Eigen library in C++. Actually, I want to calculate inverse matrix of sparse matrix. When I used Dense matrix in Eigen, I can use .inverse() operation to calculate inverse ...

I am trying to figure out the fastest method to find the determinant of sparse symmetric and real matrices in python. using scipy sparse module but really surprised that there is no determinant fun...

scipy.sparse.coo_matrix.max returns the maximum value of each row or column, given an axis. I would like to know not the value, but the index of the maximum value of each row or column. I haven't f...