Re: IC files

From: Jay Billings <jayjaybillings_at_gmail.com>
Date: Mon, 14 Sep 2009 08:44:01 -0400

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
>
Received on 2009-09-14 14:44:02

This archive was generated by hypermail 2.3.0 : 2022-09-01 14:03:42 CEST