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<HTML><HEAD><TITLE>Newmat09 - general description</TITLE></HEAD><BODY><H2>General description</H2><A HREF="which.html"> next</A> - <A HREF="which.html"> skip</A> - <A HREF="intro.html"> up</A> - <A HREF="index.html"> start</A><P>The package is intended for scientists and engineers who need tomanipulate a variety of types of matrices using standard matrixoperations. Emphasis is on the kind of operations needed in statisticalcalculations such as least squares, linear equation solve andeigenvalues.<P>It supports matrix types<PRE> Matrix (rectangular matrix) nricMatrix (variant of rectangular matrix) UpperTriangularMatrix LowerTriangularMatrix DiagonalMatrix SymmetricMatrix BandMatrix UpperBandMatrix (upper triangular band matrix) LowerBandMatrix (lower triangular band matrix) SymmetricBandMatrix RowVector (derived from Matrix) ColumnVector (derived from Matrix).</PRE>Only one element type (float or double) is supported.<P>The package includes the operations <TT>*</TT>, <TT>+</TT>, <TT>-</TT>,concatenation, inverse, transpose,conversion between types, submatrix, determinant, Choleskydecomposition, QR triangularisation, singular valuedecomposition, eigenvalues of a symmetric matrix, sorting, fast Fouriertransform, printing and an interface with <I>Numerical Recipes in C</I>.<P>It is intended for matrices in the range 15 x 15 to the maximum sizeyour machine will accommodate in a single array. On a PC using the largemodel, this is 90 x 90 (125 x 125 for triangular matrices). For Unixmachines or PCs running under a 32 bit flat model the limit isset by the size of available memory.The number of elements in an array cannotexceed the maximum size of an <I>int</I>. The package will work for verysmall matrices but becomes rather inefficient. Some of the factorisationfunctions are not (yet) optimised for paged memory and so become inefficientwhen used with very large matrices.<P>A <I>lazy evaluation</I> approach to evaluating matrix expressions isused to improveefficiency and reduce the use of temporary storage.<P>I have tested the package on variety of compilers and platforms includingAT&T, Borland, Gnu, HP, Microsoft, Sun and Watcom. For more details see thesection on <A HREF="compiler.html"> compiler performance</A>.<P><A HREF="which.html"> next</A> - <A HREF="which.html"> skip</A> - <A HREF="intro.html"> up</A> - <A HREF="index.html"> start</A><P></BODY></HTML>⌨️ 快捷键说明
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