mf_sum.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}
{* 23mar2005}{...}
{cmd:help mata sum()}
{hline}
{* index rowsum()}{...}
{* index colsum()}{...}
{* index sum()}{...}
{* index quadrowsum()}{...}
{* index quadcolsum()}{...}
{* index quadsum()}{...}
{* index quad precision}{...}

{title:Title}

{p 4 8 2}
{bf:[M-5] sum() -- Sums}


{title:Syntax}

{p 8 12 2}
{it:numeric colvector} 
{cmd:rowsum(}{it:numeric matrix Z}{cmd:)}

{p 8 12 2}
{it:numeric rowvector} 
{cmd:colsum(}{it:numeric matrix Z}{cmd:)}

{p 8 12 2}
{it:numeric scalar}{bind:      }
{cmd:sum(}{it:numeric matrix Z}{cmd:)}


{p 8 12 2}
{it:numeric colvector} 
{cmd:quadrowsum(}{it:numeric matrix Z}{cmd:)}

{p 8 12 2}
{it:numeric rowvector} 
{cmd:quadcolsum(}{it:numeric matrix Z}{cmd:)}

{p 8 12 2}
{it:numeric scalar}{bind:      }
{cmd:quadsum(}{it:numeric matrix Z}{cmd:)}


{title:Description}

{p 4 4 2}
{cmd:rowsum(}{it:Z}{cmd:)} returns a colvector containing the 
sum over the rows of {it:Z}.

{p 4 4 2}
{cmd:colsum(}{it:Z}{cmd:)} returns a rowvector containing the 
sum over the columns of {it:Z}.

{p 4 4 2}
{cmd:sum(}{it:Z}{cmd:)} returns a scalar containing the 
sum over the rows and columns of {it:Z}.

{p 4 4 2}
{cmd:quadrowsum()}, 
{cmd:quadcolsum()}, and 
{cmd:quadsum()} are quad-precision variants of 
the above functions.
The sum is accumulated in quad precision and then rounded
to double precision and returned.

{p 4 4 2}
In all cases, missing values are treated as zero.
The functions may be used with real or complex matrix {it:Z}.


{title:Remarks}

{p 4 4 2}
All functions return the same type as the argument, real if argument is real,
complex if complex.


{title:Conformability}

    {cmd:rowsum(}{it:Z}{cmd:)}, {cmd:quadrowsum(}{it:Z}{cmd:)}:
		{it:Z}:  {it:r x c}
	   {it:result}:  1 {it:x c}

{cmd:colsum(}{it:Z}{cmd:)}, {cmd:quadcolsum(}{it:Z}{cmd:)}:
		{it:Z}:  {it:r x c}
	   {it:result}:  {it:r x} 1

    {cmd:sum(}{it:Z}{cmd:)}, {cmd:quadsum(}{it:Z}{cmd:)}:
		{it:Z}:  {it:r x c}
	   {it:result}:  1 {it:x} 1


{title:Diagnostics}

{p 4 4 2}
Missing values are treated as as contributing zero to the sum; they do 
not cause the sum to become missing.


{title:Source code}

{p 4 4 2}
Functions are built-in.


{title:Also see}

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

{p 4 13 2}
Online:  help for 
{bf:{help mf_mean:[M-5] mean()}},
{bf:{help mf_cross:[M-5] cross()}};
{bf:{help m4_utility:[M-4] utility}}
{p_end}