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Hi Vladimir, > I use netCDF library (parallel, fortran version) about 4 years and it > works perfectly! > > But, on the new supercomputer i start to get very strange error. > I searched for it in my program and investigation resulted in small test > program, which creates parallel communicator and sequentially read rather > big file (16 bil integers field in 540 mb file). > > It crushes with segmentation fault on NF90_GET_VAR randomly. For example, > first run is normal, and second and third results in seg fault. > > Interestengly, that for small files (for example 1 bil integers in 200 > mb file) it works perfectly. > > Admin cant give me any helpful answers. > > Could you please to suggest where problem is? We would need to be able to duplicate the problem here, and I think that would require access to the file you are reading or to a program that creates it. Even the output from "netcdf -h" might be sufficient for us to generate an example that would demonstrate the problem. Since the Unidata developer who knew the most about parallel I/O took a different job a couple of years ago, we've been lacking in parallel I/O knowledge and experiencee, so sometimes we have to forward questions to NCAR's consultants instead. There have been a few bug fixes since netCDF-4.1.3 that relate to parallel I/O, including both the Fortran library (in netcdf-fortran-4.2) and in the netCDF-C library it calls (netCDF-4.3.0 or netCDF-4.3.1-rc2 using HDF5-1.8.11). > Write me which commands i should run to provide you information about > supercomputer and installed netCDF. It would be useful to know what version of HDF5 you are using, and whether you tried netCDF-fortran-4.2 with the netCDF C library version 4.3.0 or later. It might be interesting to know what supercomputer and operating system you are using (the output from "uname -a"), but we currently only have easy access to Linux, Mac, Solaris, and Windows systems on which to test. --Russ Russ Rew UCAR Unidata Program address@hidden http://www.unidata.ucar.edu Ticket Details =================== Ticket ID: VUY-537245 Department: Support netCDF Priority: Normal Status: Closed