<div dir="ltr"><div class="gmail_quote">On Wed, Sep 17, 2008 at 6:09 AM, Stefan Gofferje <span dir="ltr"><<a href="mailto:gradsusers@gofferje.homelinux.org">gradsusers@gofferje.homelinux.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hi,<br>
<br>
Jennifer Adams schrieb:<br>
> The 'reinit' command will release all memory, including the grib2 cache.<br>
> The maximum size of the cache is hardcoded in gaio.c:<br>
> #define MAXG2CACHE 500100100<br>
> You can change this to something smaller and recompile GrADS. At some<br>
> point, I will add a command-line switch to set the cache size on<br>
> startup, but haven't gotten to that yet. (The parsing of switches and<br>
> args on startup is a bit of a mess and needs a thorough overhaul).<br>
<br>
Now I got a statement from the provider which indicates, the memory<br>
usage was the problem. In my tests at home, grads didn't work with less<br>
than 2M of cache.<br>
I would now need some help for optimization.<br>
<br>
At the moment I do the following:<br>
I download 61 timesteps of grib2 data from NOAA and cat them into one<br>
big file. This one big file I feed into my grads script to create<br>
weather charts and meteograms. I know I could significantly reduce the<br>
mem footprint by downloading one timestep, render the charts, end grads,<br>
get the next timestep, render the charts, etc. This would even reduce<br>
the continuos CPU load.<br>
BUT for the meteograms, I need everything in one file...<br></blockquote><div><br></div><div>In your case, you could use lats4d with the g2 extension to create a scandinaian subset for your meteograms.</div><div><br></div>
<div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Anybody any ideas?<br></blockquote><div><br></div><div>One very simple solution is to add a GRIB-2 to GRIB-1 filter along the way, to convert the GRIB-2 to GRIB-1 format. Grib-2 is a good format for data transmission but is far less less optimal for day to day use. For example, the performance of your meteograms scripts will go up by a lot with grib-1. Of course, you have to factor in the cost of conversion.</div>
<div><br></div><div> Arlindo</div><div><br></div><div><br></div></div>-- <br>Arlindo da Silva<br><a href="mailto:dasilva@alum.mit.edu">dasilva@alum.mit.edu</a><br>
</div>