mata_matsave.hlp

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{smcl}
{* 07apr2005}{...}
{cmd:help mata matsave}
{hline}
{* index mata tt}{...}
{* index matsave tt}{...}
{* index matuse tt}{...}
{* index matdescribe tt}{...}
{* index .mmat files}{...}

{title:Title}

{p 4 4 2}
{bf:[M-3] mata matsave -- Save and restore matrices}


{title:Syntax}

{p 8 16 2}
: {cmd:mata} {cmd:matsave}
{it:filename}
{it:namelist}
[{cmd:,}
{cmd:replace}
]

{p 8 16 2}
: {cmd:mata} {cmd:matuse}
{it:filename}
[{cmd:,}
{cmd:replace}
]

{p 8 16 2}
: {cmd:mata} {cmdab:matd:escribe}
{it:filename}


{p 4 4 2}
where {it:namelist} is a list of matrix names as defined in 
{bf:{help m3_namelists:[M-3] namelists}}.

{p 4 4 2}
If {it:filename} is specified without a suffix, {cmd:.mmat} is assumed.

{p 4 4 2}
These commands are for use in Mata mode following Mata's colon prompt.
To use these commands from Stata's dot prompt, type

		. {cmd:mata: mata matsave} ...


{title:Description}

{p 4 4 2}
{cmd:mata} {cmd:matsave} saves the specified global matrices in 
{it:filename}.

{p 4 4 2}
{cmd:mata} {cmd:matuse} loads the matrices stored in {it:filename}.

{p 4 4 2}
{cmd:mata} {cmd:matdescribe} describes the contents of {it:filename}.


{title:Option for mata matsave}

{p 4 8 2}
{cmd:replace} specifies that {it:filename} may be replaced if it already exists.


{title:Option for mata matuse}

{p 4 8 2}
{cmd:replace} specifies that any matrices in memory with the same name as
those stored in {it:filename} can be replaced.


{title:Remarks}

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These commands are for interactive use; they are not for use 
inside programs.  See {bf:{help mf_fopen:[M-5] fopen()}} for Mata's
programming functions for reading and writing files.
In the programming environment, 
if you have a matrix {it:X} and want to write it to file
mymatrix.myfile, you code 

		{cmd}fh = fopen("mymatrix.myfile", "w")
		fputmatrix(fh, X)
		fclose(fh){txt}

{p 4 4 2}
Later, you can read it back by coding

		{cmd}fh = fopen("mymatrix.myfile", "r")
		fgetmatrix(fh, X)
		fclose(fh){txt}

{p 4 4 2}
{cmd:mata} {cmd:matsave}, 
{cmd:mata} {cmd:matuse}, 
and
{cmd:mata} {cmd:matdescribe} 
are for use outside of programs, when you are working interactively.
You can save your global matrices

	: {cmd:mata matsave mywork *}
	(saving A, X, Z, beta)
	file mywork.mmat saved

{p 4 4 2}
and then later get them back

	: {cmd:mata matuse mywork}
	(loading A, X, Z, beta)

{p 4 4 2}
{cmd:mata} {cmd:matdescribe} will tell you the contents of a file

	: {cmd:mata matdescribe mywork}
	file mywork.mmat saved on 4 Apr 2005 08:46:39 contains 
	X, X, Z, beta


{title:Diagnostics}

{p 4 4 2}
{cmd:mata} {cmd:matsave} saves the contents of view matrices.  Thus
when they are restored by {cmd:mata} {cmd:matuse}, the contents will be
correct regardless of the data Stata has loaded in memory.


{title:Source code}

{p 4 4 2}
{view mata_matsave.ado, adopath asis:mata_matsave.ado},
{view mata_matuse.ado, adopath asis:mata_matuse.ado},
{view mata_matdescribe.ado, adopath asis:mata_matdescribe.ado},
{view mmat_.mata, adopath asis:mmat_.mata}


{title:Also see}

{p 4 13 2}
Manual:  {hi:[M-3] mata matsave}

{p 4 13 2}
Online:  help for 
{bf:{help m3_intro:[M-3] intro}}
{p_end}