search for: densified

Hello I would like to calculate a weighted line integral. The integral is calculated by the cells that this lines trasverses (the small cells belong to matrix (m*n) that represent the value that a specific area has. I need to calculate the weights by finding out how much the line touches or impinges inside a cell. The weight is less if a line just touches one of the four edges of a square

Dear list, Can anyone tell me how to obtain the rank of a sparse Matrix, for example from package Matrix (class dgCMatrix)? Here is an example of QR decomposition of a sparse matrix (from the sparseQR class help). library(Matrix) data(KNex) mm <- KNex$mm str(mmQR <- qr(mm)) Similarly, using the functions/classes from the relatively new MatrixModels package: library(MatrixModels)