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<HTML><HEAD><TITLE>Newmat09 - constructors</TITLE></HEAD><BODY><H2>Constructors</H2><A HREF="elements.html"> next</A> - <A HREF="elements.html"> skip</A> - <A HREF="refer.html"> up</A> - <A HREF="index.html"> start</A><P>To construct an m x n matrix, <TT>A</TT>, (m and n are integers) use<PRE> Matrix A(m,n);</PRE>The UpperTriangularMatrix, LowerTriangularMatrix, SymmetricMatrix andDiagonalMatrix types are square. To construct an n x n matrix use,for example<PRE> UpperTriangularMatrix UT(n); LowerTriangularMatrix LT(n); SymmetricMatrix S(n); DiagonalMatrix D(n);</PRE>Band matrices need to include bandwidth information in theirconstructors.<PRE> BandMatrix BM(n, lower, upper); UpperBandMatrix UB(n, upper); LowerBandMatrix LB(n, lower); SymmetrixBandMatrix SB(n, lower);</PRE>The integers upper and lower are the number of non-zero diagonals aboveand below the diagonal (excluding the diagonal) respectively.<P> The RowVector and ColumnVector types take just one argument in theirconstructors:<PRE> RowVector RV(n); ColumnVector CV(n);</PRE>You can also construct vectors and matrices without specifying thedimension. For example<PRE> Matrix A;</PRE>In this case the dimension must be set by an<A HREF="copy.html">assignment statement</A> or a<A HREF="dimen.html">re-dimension statement</A>.<P>You can also use a constructor to set a matrix equal to another matrixor matrix expression.<PRE> Matrix A = UT; Matrix A = UT * LT;</PRE>Only conversions that don't lose information are supported - eg youcannot convert an upper triangular matrix into a diagonal matrix using =.<P><A HREF="elements.html"> next</A> - <A HREF="elements.html"> skip</A> - <A HREF="refer.html"> up</A> - <A HREF="index.html"> start</A><P></BODY></HTML>⌨️ 快捷键说明
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