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csr-matrix

Compressed sparse row matrix class

csr-matrix

A very minimal incremental compressed sparse row matrix library for JavaScript.

Install

npm i csr-matrix

Example

var dict = {}
dict[[1,2]] = 1
dict[[0,0]] = 2.5
dict[[3,4]] = 5
 
var CSRMatrix = require("csr-matrix")
 
var M = CSRMatrix.fromDictionary(dict, 4, 5)
console.log(M.apply([1,2,3,4,5], []))

API

CSRMatrices are optimized for exactly one thing: fast matrix-vector multiplies. The way you do this is by calling the following method:

Constructors

There are several ways to create csr-matrices. The most direct way to do this is to just call the constructor yourself:

CSRMatrix.fromList(items[, nrows, ncols])

Turns an array of entries of the form [row, column, value] into a sparse matrix. Note that if there are some zero rows or columns at the end of the matrix, you need to specify the number of rows/columns in the optional nrows/ncols arguments.

CSRMatrix.fromDictionary(dict[, nrows, ncols])

Converts a JavaScript object with entries for the form "row,column" into a sparse matrix.

CSRMatrix.fromDense(mat)

Turns an array-of-arrays into a csr matrix

CSRMatrix.fromNDArray(ndarr)

Turns a 2D dimensional ndarray into a csr matrix

Method

matrix.apply(vector[, result])

This computes the normal matrix-vector product, but is often much faster than a dense multiply since the matrix is stored in a compressed sparse format.

  • vector is the vector to be multiplied
  • result is an optional array which gets the result. If not specified, a new vector gets allocated

Returns the resulting product

matrix.transpose()

Returns the transpose of the matrix

matrix.rowCount

Returns the number of rows

matrix.columnCount

Returns the number of columns

matrix.toList()

Converts matrix into a list format

matrix.toDictionary()

Converts matrix into hash table

matrix.toDense()

Converts matrix into array of arrays

matrix.toNDArray(out)

Converts matrix into ndarray

  • out is the output ndarray

Credits

(c) 2013-2015 Mikola Lysenko. BSD