From octave-sources-request at bevo dot che dot wisc dot edu Mon Jul 21 07:34:13 2003
Subject: Re: num2str
From: Fabian at isas-berlin dot de
To: octave-sources at bevo dot che dot wisc dot edu
Cc: M dot Jueschke at DPI dot Physik dot Uni-Goettingen dot de
Date: Mon, 21 Jul 2003 03:53:57 -0500

> Since I didn't find a num2str for octave which handeles matrices and
> complex numbers, I have written one.


Function  'mat2str'  from Octave-Forge ( 2003-June-2 )
handles complex matrices

It has been also published as
<http://www.octave.org/mailing-lists/octave-sources/2002/28>.


'mat2str' is vectorized ( no for-loops ) in contrast to 'num2str'.


On my system, I get the following tictoc-times:

:> N=200; x=randn(N)+randn(N)*i;
:> tic; y=num2str(x); TICTOC_NUM2STR=toc
            TICTOC_NUM2STR = 22.0	sec
:>> tic; y=mat2str(x); TICTOC_MAT2STR=toc
            TICTOC_MAT2STR = 4.07	sec

i.e. 'mat2str' is 5.4 x faster than 'num2str' for the
same 200x200 complex matrix input.

In addition  'mat2str' encloses output string in a pair 
of brackets in order to make it siutable as 'eval' input and
adds commas and semicolons  to more clearly
seperate matrix elements. 

As another plus,  'mat2str' allows to specify the number of
decimals to be printed as an input argument.



Rolf 
<Fabian at ISAS-Berlin dot de>