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Re: Use of NcVar::Put method

> From: Laurent LE GAL <address@hidden>
> To: Russ Rew <address@hidden>
> Subject: Re: Use of NcVar::Put method

Hi Laurent,

> still using NetCDF, I'd like to know if there's a way to memory map
> (mmap) a NetCDF matrix to accelerate data access. In our application we
> manipulate large amounts of data (typically 50Mb of sonar data) and need
> to access them very quickly. We use to memory map these data but with
> NetCDF, the only solution we found is to read the data matrix (without
> all the header information) in a memory mapped file and then use this
> file to access the data. This copy stage is of course not very
> effective. So we are looking for an other solution avoiding this copy
> operation.

Sorry, but we have not used mmap calls in netCDF, because we needed
netCDF to work on systems that don't support memory mapping.  

However, I'm forwarding this reply to Glenn Davis, because he did some
experiments with this at one time and may have a suggestion for how to
most easily modify netCDF to use memory mapping.

--Russ

_____________________________________________________________________

Russ Rew                                         UCAR Unidata Program
address@hidden                     http://www.unidata.ucar.edu