# how to use matrix market matrices in matlab

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How to use Matrix Market matrices in Matlab. The Matrix Market is an interesting collection of matrices from a variety of applications. Purpose. To illustrate the use of Matrix Market matrices in Matlab To learn a bit about sparse matrices - PowerPoint PPT PresentationTRANSCRIPT

How to use Matrix Market matrices in MatlabThe Matrix Market is an interesting collection of matrices from a variety of applications

PurposeTo illustrate the use of Matrix Market matrices in MatlabTo learn a bit about sparse matricesTo use some of the tools available in Matlab for working with sparse matrices

Preliminary StepsLocate a matrix at the Matrix Market web site math.nist.gov/MatrixMarket (see the Introduction to the Matrix Market tutorial)Download and uncompress a file describing the matrix (see the Downloading matrices from the Matrix Market tutorial)Load the matrix into Matlab (see Converting Matrix Market matrices to Matlab tutorial and this tutorial)

In Matlab we will illustrateThe structure of sparse matrices (using spy)Solving large linear systems (using \)The time required (using tic and toc)The accuracy of the calculated solution (using norm and condest)Fill-in in the factorization (using lu, nnz and spy)The effect of column reordering on fill-in (using colmmd, lu, nnz and spy)The time required for the solution when sparsity is not used (using full)

The structure of sparse matrices

Time and accuracy of solving a system of equations

Non-zero structure of A

Fill-in

Fill-in

Column reordering

The value of sparsity

Other tutorials available at www.math.sjsu.edu/~fosterIntroduction to the Matrix MarketDownloading matrices from the Matrix MarketConverting Matrix Market matrices to Matlab formatIterative methods in Matlab with Matrix Market matrices

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