Hi again. The previous message got mangled and should read EpetraExt::MatrixMarketFileToCrsMatrix(argv[2], mMap, mMap, nMap, pNull); (where argv[2] is the MM file name). My apologies, -Tudor -- Tudor N. Buican, PhD Managing Member SEA LLC phone: 505-271-9925, 505-818-7303 fax: 505-271-9925 email: tudor at timb.com