# 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 Presentation

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• 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