Re: [Gnuplot-info] Plot matrix with GNUplot. Slow

[Yonghui <lyh...@gm...>]

Thanks Ethan,

I am actually making a movie. 200 pictures, each picture is the 100x100
matrix. Here is the command:
-----------plot_TDM.gp--------------
set term gif size 640,640 animate delay 10
set out '@movie_TDM.gif'
unset key

set cbrange[-0.01:0.01]
i=0
set pm3d
unset surface
set view map
set palette defined (-0.01 "red", 0 "white", 0.01 "blue")
load "plot_TDM_loop.gp"
unset out
quit

------------plot_TDM_loop.gp"----------------
splot '_TDTDM.dat' matrix ind i*10
print i
i=i+1
if (i<200) reread

Please take a look. Thanks.

Yonghui

-----Original Message-----
From: Ethan A Merritt [mailto:eam...@gm...] 
Sent: Friday, May 17, 2013 12:18 AM
To: gnu...@li...
Cc: FortCpp
Subject: Re: [Gnuplot-info] Plot matrix with GNUplot. Slow

On Thursday, 16 May 2013, FortCpp wrote:
> I am using GNUplot for plotting a small matrix. The matrix is 100x100 
> by size. e.g.
> 
> 1.23212 2.43123 -1.24312 ......
> -4.23123 2.00458 5.60234 ......
> ......
> The data is not neatly stored in the file. So from C++ point of view, 
> due to the lack of length per data, there is no way to load a whole 
> number, but it has to check when the number is loading. I guess this 
> should be the reason of the slow plotting speed.
> 
> Now I have 3 questions:
> Q1: Is loading the bottle neck?
> 
> Q2: If I can make the data file neatly stored (setw). e.g.
> 
>  1.23212  2.43123 -1.24312 ......
> -4.23123  2.00458  5.60234 ......
> ......
> Does the plotting speed get any improvement? (Maybe GNUplot can check 
> what the pattern is. Thus improve the loading speed. Not sure.)

No. That won't make any difference.

> 
> Q3: Any other options that I can set to make it faster?

gnuplot> help fpe

 The `set datafile nofpe_trap` command tells gnuplot not to re-initialize a
floating point exception handler before every expression evaluation used
while  reading data from an input file.  This can significantly speed data
input from  very large files at the risk of program termination if a
floating-point  exception is generated.

You haven't shown us the commands you use to read the file, so I don't know
if this is relevant to your case.

There is a recent patch in the CVS version that hugely speeds up reading
binary matrices, but since the matrix you show is in ascii that wouldn't
help.

	Ethan


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