mf_diagonal.hlp

是一个经济学管理应用软件 很难找的 但是经济学学生又必须用到

{smcl}
{* 15mar2005}{...}
{bf:help mata diagonal()}
{hline}
{* index diagonal()}{...}
{* index extract diagonal}{...}
{* index diagonal matrix}{...}
{* index diagonal}{...}

{title:Title}

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{bf:[M-5] diagonal() -- Extract diagonal into column vector}


{title:Syntax}

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{it:numeric colvector}
{cmd:diagonal(}{it:numeric matrix A}{cmd:)}


{title:Description}

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{cmd:diagonal(}{it:A}{cmd:)} 
extracts the diagonal of {it:A} and returns it in a column vector.


{title:Remarks}

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{cmd:diagonal()}
may be used with nonsquare matrices.

{p 4 4 2}
Do not confuse {cmd:diagonal()} with its functional inverse, 
{cmd:diag()}; see 
{bf:{help mf_diag:[M-5] diag()}}.
{cmd:diagonal()} extracts the diagonal of a matrix into a vector;
{cmd:diag()} creates a diagonal matrix from a vector.


{title:Conformability}

    {cmd:diagonal(}{it:A}{cmd:)}:
		{it:A}:  {it:r x c}
	   {it:result}:  min({it:r},{it:c}) {it:x} 1


{title:Diagnostics}

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None.


{title:Source code}

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{cmd:diagonal()} is built in.


{title:Also see}

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Manual:  {hi:[M-5] diagonal()}

{p 4 13 2}
Online:  help for 
{bf:{help mf_diag:[M-5] diag()}},
{bf:{help mf_isdiagonal:[M-5] isdiagonal()}},
{bf:{help mf_blockdiag:[M-5] blockdiag()}};
{bf:{help m4_manipulation:[M-4] manipulation}}
{p_end}