Re: [ferret_users] Number of files

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hello Faisal,
Jaison offers some good suggestions. In Ferret versions 5.51 and later, 
we can have 100 datasets open at a time; before that version the limit 
was 30. If you are using a version of Ferret older than v5.51, upgrading 
to a more recent one will fix this.  To see the version number, look at 
the lines that are output when you start Ferret.

Ansley

Jaison Kurian wrote:
> Hi Faisal,
>            The given details are not sufficient to suggest a better
> solution to your problem. Anyway...making some wild guess gives
> the following answers.
>
>   From the error messgae it seems to be NetCDF files. If your individual 
> files are for same XYZ region and differs only in "time", then you have 
> two options to do calculations involving all 40 files at the same time :
>
>   1. Using a Descriptor file  
>   --------------------------
>   This file ties all the specified NetCDF files into a single file along 
>   time axis. It is pretty easy to create one. Details about descriptor file
>   and its bounds are given in the User Manual at
>
>         Ch10 Sec4.  CREATING A MULTI-FILE NETCDF DATA SET
>         Ch4  Sec4.  FERRET PROGRAM LIMITS 
>   
>   This will give basic ideas and an example for the descriptor file. 
>   You can also try serching in Mail Archive/FAQ for some usefull 
>   informations, especially for tools to make descriptor files. Also 
>   note that this is the ideal solution for files with considerable size.
>
>   2. Merging to a single NetCDF file
>   ----------------------------------
>   You can open the individual datasets in Ferret and can append data to 
>   a common output NetCDF file. Then you can use the new file for calcul-
>   ations. This process is very easy if you have proper time axis for 
>   each of the 40 NetCDF files. If it does not have one, then you have to
>   define a destination time axis and you have to assign the time axis 
>   to data from individual files before appending to the new file. This
>   method is not appreciable if the individual/combined file size is 
>   pretty large.
>
> Try searching in the mail archives 
> (http://ferret.pmel.noaa.gov/cgi-bin/marc-search.cgi) with key words like
> "32 files" or "too many connects" to see previous mails discussing about
> similar problem. 
>   Which version of Ferret are you using ? According to the documentation
> for Ferret version 6.00, the maximum number of  data sets simultaneously 
> open (as seen through SHOW DATA) is 100. I haven't checked this yet. So,
> you can give try by switching to new versions....
>
>   If this mail/User Manual/Mail Archive/FAQ didn't help you to solve
> your problem, write back with "ALL RELEVANT DETAILS".
>
> Regards,
>
> Jaison   
>   
> On Tue, 28 Nov 2006, S. Faisal Saeed wrote:
>
>   
> > Dear all,
> >
> > It seems that ferret does open more than 33 files at a time. It gives 
> > an error of too many connects. I want to open 40 files and do some 
> > averaging, is there any simple solution ?
> >
> > Regards,
> > Faisal
> >
> >     
--

~>   ~>   ~>   ~>   ~>   ~>   ~>   ~>   ~>   ~>   ~> 
Ansley Manke, NOAA/PMEL   ansley.b.manke@noaa.gov
7600 Sand Point Way NE, Seattle WA
Phone 206-526-6246,  FAX 206-526-6744