Re: New Subfind (Gadget-4) replicating blocks?

From: Volker Springel <vspringel_at_MPA-Garching.MPG.DE>
Date: Mon, 30 Nov 2020 13:31:16 +0100

Hi Tiago,

Thanks for pointing this out. The second occurrence of the tag "FMAS" is really a different field, namely "GroupAscale", which gives the scale factor of the halo (this is only really of interest for lightcone group catalogues). The corresponding file-format-2 identifier has now been renamed FMAA to avoid it's duplicate use. Of course, this small issue is only noticeable if you use the fileformat 2 to begin with... (I'd recommend to switche to HDF5, format 3).

Best,
Volker

> On 30. Nov 2020, at 13:00, Tiago Castro <tiagobscastro_at_gmail.com> wrote:
>
> Dear list,
>
> It seems that the new subfind is writing twice the block FMAS (see the list of variables I find inside the subfind snapshot). Is that happening to anybody else or have I done something wrong (the Config file used to compile is also attached here)?
>
> cheers,
> # BLOCK OFFSET SIZE
> -------------------------
> 1 HEAD 20 80
> 2 FLEN 124 20920
> 3 FMAS 21068 20920
> 4 FPOS 42012 62760
> 5 FVEL 104796 62760
> 6 FLTY 167580 125520
> 7 FLOT 293124 251040
> 8 FMTY 544188 125520
> 9 FMAS 669732 20920
> 10 FMM2 690676 20920
> 11 FRM2 711620 20920
> 12 FMC2 732564 20920
> 13 FRC2 753508 20920
> 14 FMC5 774452 20920
> 15 FRC5 795396 20920
> 16 FMT2 816340 20920
> 17 FMR2 837284 20920
> 18 FNSH 858228 20920
> 19 FFSH 879172 41840
> 20 SGNR 921036 50816
> 21 SGRG 971876 25408
> 22 SLEN 997308 25408
> 23 SMAS 1022740 25408
> 24 SPOS 1048172 76224
> 25 SVEL 1124420 76224
> 26 SLTY 1200668 152448
> 27 SLOT 1353140 304896
> 28 SMTY 1658060 152448
> 29 SCMP 1810532 76224
> 30 SSPI 1886780 76224
> 31 SSPI 1963028 25408
> 32 SVMX 1988460 25408
> 33 SVRX 2013892 25408
> 34 SHMR 2039324 25408
> 35 SHMT 2064756 152448
> 36 SIDM 2217228 25408
> 37 SPRT 2242660 25408
> -------------------------
>
> #--------------------------------------- Basic operation mode of code
>
> PERIODIC # enables periodic boundary condistions
> NTYPES=6 # number of particle types
> RANDOMIZE_DOMAINCENTER # shifts the particle distribution randomly each step to reduce correlations of force errors in time
> LEAN # selects a special 'lean' mode of code operation, which is optimized for aggressive memory saving
> GADGET2_HEADER # allows reading of snapshots with GADGET-2/3 header format
> #--------------------------------------- Gravity calculation
> SELFGRAVITY # switch to enable self-gravity of particles (typically always on)
> FMM # enables Fast Multipole Method instead of one-sided tree algorithm
> MULTIPOLE_ORDER=2 # sets the multipole order of Tree or FMM computations
> #--------------------------------------- TreePM Options
>
> PMGRID=512 # basic mesh size for TreePM calculations
> ASMTH=1.25 # sets the smoothing of the PM force and thus the split-scale between Tree/FMM force and PM force
> RCUT=6.0 # cut-off radius beyond which Tree or FMM evaluations are stopped in TreePM / FMM-PM
> NTAB=128 # size of short-range look-up table
> TREE_NUM_BEFORE_NODESPLIT=4 # number of particles are are at most allowed in a tree node before it is split (can be 1)
>
> #--------------------------------------- Time integration options
>
> HIERARCHICAL_GRAVITY # enables hierarchical time integration of the gravity
>
> #--------------------------------------- Treatment of gravitational softening
>
> NSOFTCLASSES=1 # number of different softening classes
>
> #---------------------------------------- Single/double precision and data types
>
> DOUBLEPRECISION=1 # if activated and set to 1, use double precision internally, for 2 use mixed precision, otherwise single precision
>
> #---------------------------------------- Output/Input options
>
> OUTPUT_TIMESTEP # output timesteps
> POWERSPEC_ON_OUTPUT # computes a matter power spectrum when the code writes a snapshot output
>
> #---------------------------------------- On the fly FOF groupfinder
>
> FOF # enable FoF output
> FOF_PRIMARY_LINK_TYPES=2 # bitmask, 2^type for the primary dark matter type
> FOF_GROUP_MIN_LEN=100 # minimum group length (default is 32)
> FOF_LINKLENGTH=0.2 # linking length for FoF (default=0.2)
>
> #---------------------------------------- Subfind
>
> SUBFIND # enables substructure finder
> SUBFIND_HBT # use previous subhalo catalogue instead of density excursions to define subhalo candidates
>
> #---------------------------------------- Merger tree code
>
> MERGERTREE # enables on-the-fly calculation of descendants, and merger tree construction from group catalogues
>
> #--------------------------------------- IC creation
>
> NGENIC=512 # generate cosmological ICs, set NGENIC to the FFT grid size used for IC generation
> NGENIC_2LPT # applies 2LPT instead of just Zeldovich approximation
> CREATE_GRID # start with a regular Cartesian DM particle grid, instead of reading a glass file (for NGENIC)
>
> #----------------------------------------Parallelization options
>
> IMPOSE_PINNING # enables pinning of MPI processes to CPU cores
> Tiago Castro Post Doc, Department of Physics / UNITS / OATS
> Phone: (+39 040 3199 120)
> Mobile: (+39 388 794 1562)
> Email: tiagobscastro_at_gmail.com
> Website: tiagobscastro.com
> Skype: tiagobscastro
> Address: Osservatorio Astronomico di Trieste / Villa Bazzoni
> Via Bazzoni, 2, 34143 Trieste TS
>
>
>
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Received on 2020-11-30 13:31:17

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