Re: IC files

From: Jay Billings <jayjaybillings_at_gmail.com>
Date: Wed, 16 Sep 2009 07:05:42 -0400

Congrats! Ubuntu will make it much easier! :)

Jay

P.S. - If you do need to use it on Windows, it should be pretty simple to
cross-compile it with some of the newer compiler tools on Linux.

On Tue, Sep 15, 2009 at 10:06 PM, Dimitry Ayzenberg <dayzenbe_at_andrew.cmu.edu
> wrote:

>
> I'm actually using Ubuntu now. Gave up on getting it to work on Windows.
> But that explains it to me really well. Thanks for the help.
>
> Dimitry
>
>
> On Tue, September 15, 2009 21:39, Scott Wales wrote:
> >
>
> > Hi Dimitry,
> >
> >
> > The blocks should be big enough to hold the data for all particles.
> > Gadget probably checks the block size is exactly that amount.
> >
> >
> > The header must be 256 bytes (a struct with the correct format is
> > defined in allvars.h), for the rest check the user's guide, for example
> the
> > positions block should be 3*N*sizeof(float) bytes, where N is the sum of
> > elements in header.npart.
> >
> > fprintf outputs text, to output binary data use fwrite (since you're on
> > windows make sure to open the file as binary data).
> >
> > Scott
> >
> >
> >
> > On 16/09/2009, at 11:05 AM, Dimitry Ayzenberg wrote:
> >
> >
> >>
> >> I think I've pretty much got it under control. Thanks for the help.
> >> I just
> >> had a couple of questions.
> >>
> >> The blocks for the Iinitial condition file can be any size as long
> >> as the block size before them contains what size they are? Or must they
> >> all be the same, specific size? Or does just the header block have to be
> >> that specific size, which is 256 bytes?
> >>
> >> Also, does just doing an fprintf in C put the Initial Condition file
> >> in the right format? It seems to read as if it's just a text file. Is
> >> there anything special I need to add so that it prints out in the right
> >> format?
> >>
> >> Thanks,
> >> Dimitry
> >>
> >>
> >> On Mon, September 14, 2009 08:44, Jay Billings wrote:
> >>
> >>> If you have any problems, I can link you to some source code that
> >>> should help you with the IO.
> >>>
> >>> Jay
> >>>
> >>>
> >>>
> >>> On Mon, Sep 14, 2009 at 8:25 AM, Dimitry Ayzenberg
> >>> <dayzenbe_at_andrew.cmu.edu>wrote:
> >>>
> >>>
> >>>
> >>>>
> >>>> I think I'll try that out. I can't seem to open it properly in
> >>>> Fortran.
> >>>>
> >>>>
> >>>>
> >>>> Thanks,
> >>>> Dimitry
> >>>>
> >>>>
> >>>>
> >>>> On Mon, September 14, 2009 07:25, Jay Billings wrote:
> >>>>
> >>>>
> >>>>> Dimitry,
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> It is also rather trivial to "invert" the read_snapshot.c file
> >>>>> found in the "Analysis" directory. One benefit of doing it like
> >>>>> this is that you have both read and write routines for Gadget2.
> >>>>>
> >>>>> Jay
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> On Mon, Sep 14, 2009 at 1:19 AM, Dimitry Ayzenberg
> >>>>> <dayzenbe_at_andrew.cmu.edu>wrote:
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>>
> >>>>>> Thank you very much. That helps a lot. I'm actually using
> >>>>>> Gadget
> >>>>>> to try to do planet formation simulations, so I'll probably mess
> >>>>>> with the initial conditions on my own. Just needed to know how
> >>>>>> to actually access them.
> >>>>>>
> >>>>>> Dimitry
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> On Mon, September 14, 2009 01:10, Scott Wales wrote:
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>>
> >>>>>>
> >>>>>>> Hi Dimitry,
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> Gadget initial condition files have the same format as
> >>>>>>> snapshots. They
> >>>>>>> are binary files, so you'll have to write a program to
> >>>>>>> actually do
> >>>>>>>
> >>>>>> anything
> >>>>>>> with them. The file format is detailed in the user's guide,
> >>>>>>> but briefly the file consists of a series of blocks, each of
> >>>>>>> which consist of an int containing the block size, a binary
> >>>>>>> blob of data and then another int
> >>>>>> with
> >>>>>>> the block size. Fortran will read the blocks automatically
> >>>>>>> with a unformatted read, for c use a function like
> >>>>>>>
> >>>>>>> #include <assert.h>
> >>>>>>> #include <stdio.h>
> >>>>>>> void ReadGadgetBlock(FILE* gadgetfile, void ** data, size_t *
> >>>>>>> data_size){ unsigned int block_size; size_t number_read; //
> >>>>>>> Get
> >>>>>>> the size of the block number_read =
> >>>>>>> fread(&block_size,1,sizeof(block_size),gadgetfile);
> >>>>>>> assert(number_read == 1); // Allocate space for the data
> >>>>>>> *data_size = block_size;
> >>>>>>> *data = realloc(*data,*data_size);
> >>>>>>> // Read the data
> >>>>>>> number_read = fread(*data,*data_size,1,gadgetfile);
> >>>>>>> assert(number_read == *data_size);
> >>>>>>> // Read the block footer
> >>>>>>> number_read =
> >>>>>>> fread(&block_size,1,sizeof(block_size),gadgetfile);
> >>>>>>> assert(number_read == 1); assert(block_size == *data_size); }
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> The contents of each block are detailed in the user's guide.
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> The initial conditions you'll use depends on what you're
> >>>>>>> simulating. For cosmological simulations try something like
> >>>>>>> Edwin
> >>>>>>> Sirko's ic
> >>>>>>> (needs some format conversion) or Crocce et al.'s 2lpt. They
> >>>>>>> will require input power spectra, found by something like
> >>>>>>> cmbeasy or cmbfast.
> >>>>>>>
> >>>>>>> Cheers,
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> Scott Wales
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> On 14/09/2009, at 2:40 PM, Dimitry Ayzenberg wrote:
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>>
> >>>>>>>> Can someone please tell me how to open and read the .dat
> >>>>>>>> files in the ICs folder? Also how to make initial condition
> >>>>>>>> files? I'm a little confused about how to do either.
> >>>>>>>>
> >>>>>>>> Thanks,
> >>>>>>>> Dimitry
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> -----------------------------------------------------------
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> If you wish to unsubscribe from this mailing, send mail to
> >>>>>>>> minimalist_at_MPA-Garching.MPG.de with a subject of:
> >>>>>>>> unsubscribe gadget-list A web-archive of this mailing list
> >>>>>>>> is available here:
> >>>>>>>> http://www.mpa-garching.mpg.de/gadget/gadget-list
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> -----------------------------------------------------------
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>> If you wish to unsubscribe from this mailing, send mail to
> >>>>>>> minimalist_at_MPA-Garching.MPG.de with a subject of: unsubscribe
> >>>>>>>
> >>>>>> gadget-list
> >>>>>>> A web-archive of this mailing list is available here:
> >>>>>>> http://www.mpa-garching.mpg.de/gadget/gadget-list
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>>
> >>>>>>
> >>>>>>
> >>>>>> --
> >>>>>> Dimitry Ayzenberg
> >>>>>> Carnegie Mellon University
> >>>>>> Physics - Class of 2012
> >>>>>> Cell:(732)-425-4534
> >>>>>> Email: dayzenbe_at_andrew.cmu.edu
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> -----------------------------------------------------------
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> If you wish to unsubscribe from this mailing, send mail to
> >>>>>> minimalist_at_MPA-Garching.MPG.de with a subject of: unsubscribe
> >>>>>> gadget-list A web-archive of this mailing list is available
> >>>>>> here:
> >>>>>> http://www.mpa-garching.mpg.de/gadget/gadget-list
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>
> >>>>
> >>>>
> >>>> --
> >>>> Dimitry Ayzenberg
> >>>> Carnegie Mellon University
> >>>> Physics - Class of 2012
> >>>> Cell:(732)-425-4534
> >>>> Email: dayzenbe_at_andrew.cmu.edu
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> -----------------------------------------------------------
> >>>>
> >>>>
> >>>>
> >>>> If you wish to unsubscribe from this mailing, send mail to
> >>>> minimalist_at_MPA-Garching.MPG.de with a subject of: unsubscribe
> >>>> gadget-list A web-archive of this mailing list is available here:
> >>>> http://www.mpa-garching.mpg.de/gadget/gadget-list
> >>>>
> >>>>
> >>>>
> >>>
> >>
> >>
> >> --
> >> Dimitry Ayzenberg
> >> Carnegie Mellon University
> >> Physics - Class of 2012
> >> Cell:(732)-425-4534
> >> Email: dayzenbe_at_andrew.cmu.edu
> >>
> >>
> >>
> >>
> >>
> >> -----------------------------------------------------------
> >>
> >>
> >> If you wish to unsubscribe from this mailing, send mail to
> >> minimalist_at_MPA-Garching.MPG.de with a subject of: unsubscribe
> >> gadget-list A web-archive of this mailing list is available here:
> >> http://www.mpa-garching.mpg.de/gadget/gadget-list
> >>
> >
> >
> >
> >
> > -----------------------------------------------------------
> >
> >
> > If you wish to unsubscribe from this mailing, send mail to
> > minimalist_at_MPA-Garching.MPG.de with a subject of: unsubscribe
> gadget-list
> > A web-archive of this mailing list is available here:
> > http://www.mpa-garching.mpg.de/gadget/gadget-list
> >
> >
> >
>
>
> --
> Dimitry Ayzenberg
> Carnegie Mellon University
> Physics - Class of 2012
> Cell:(732)-425-4534
> Email: dayzenbe_at_andrew.cmu.edu
>
>
>
>
> -----------------------------------------------------------
>
> If you wish to unsubscribe from this mailing, send mail to
> minimalist_at_MPA-Garching.MPG.de with a subject of: unsubscribe gadget-list
> A web-archive of this mailing list is available here:
> http://www.mpa-garching.mpg.de/gadget/gadget-list
>
Received on 2009-09-16 13:05:43

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