mf_makesymmetric.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}
{* 16mar2005}{...}
{cmd:help mata makesymmetric()}
{hline}
{* index makesymmetric()}{...}
{* index _makesymmetric()}{...}
{* index symmetric matrices}{...}
{* index Hermitian matrices}{...}

{title:Title}

{p 4 8 2}
{bf:[M-5] makesymmetric() -- Make square matrix symmetric (Hermitian)}


{title:Syntax}

{p 8 12 2}
{it:numeric matrix}{bind: }
{cmd:makesymmetric(}{it:numeric matrix A}{cmd:)}

{p 8 12 2}
{it:void}{bind:          }
{cmd:_makesymmetric(}{it:numeric matrix A}{cmd:)}


{title:Description}

{p 4 4 2}
{cmd:makesymmetric(}{it:A}{cmd:)} returns 
{it:A} made into a symmetric (Hermitian) matrix by reflecting the 
elements below the diagonal.

{p 4 4 2}
{cmd:_makesymmetric(}{it:A}{cmd:)} does the same thing, but stores the 
result back in {it:A}.


{title:Remarks}

{p 4 4 2}
If {it:A} is real, elements below the diagonal are copied into their
corresponding above-the-diagonal position.

{p 4 4 2}
If {it:A} is complex, the conjugate of the elements below the diagonal are 
copied into their corresponding above-the-diagonal positions, and the 
imaginary part of the diagonal is set to zero.

{p 4 4 2}
Whether {it:A} is real or complex, 
roundoff error can make matrix calculations that are supposed to produce 
symmetric matrices produce matrices that vary a little from
symmetry, and {cmd:makesymmetric()} can be used to correct the situation.


{title:Conformability}

    {cmd:makesymmetric(}{it:A}{cmd:)}:
		{it:A}:  {it:n x n}
	   {it:result}:  {it:n x n}

    {cmd:_makesymmetric(}{it:A}{cmd:)}:
		{it:A}:  {it:n x n}


{title:Diagnostics}

{p 4 4 2}
{cmd:makesymmetric(}{it:A}{cmd:)} and {cmd:_makesymmetric(}{it:A}{cmd:)} abort
with error if {it:A} is not square.  In addition, {cmd:_makesymmetric()}
aborts with error if {it:A} is a view.


{title:Source code}

{p 4 4 2}
{view makesymmetric.mata, adopath asis:makesymmetric.mata};
{cmd:_makesymmetric()} is built-in.


{title:Also see}

{p 4 13 2}
Manual:  {hi:[M-5] makesymmetric()}

{p 4 13 2}
Online:  help for 
{bf:{help mf_issymmetric:[M-5] issymmetric()}};
{bf:{help m4_manipulation:[M-4] manipulation}}
{p_end}