param_ngenic.txt 4.14 KB
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Nmesh            128                        % This is the size of the FFT grid used to 
                                            % compute the displacement field. One
                                            % should have Nmesh >= Nsample.

Nsample          128                        % sets the maximum k that the code uses,
                                            % i.e. this effectively determines the
                                            % Nyquist frequency that the code assumes,
                                            % k_Nyquist = 2*PI/Box * Nsample/2
                                            % Normally, one chooses Nsample such that
                                            % Ntot =  Nsample^3, where Ntot is the
                                            % total number of particles
 

Box              50000.0                    % Periodic box size of simulation
FileBase         ics                        % Base-filename of output files
OutputDir        ../                        % Directory for output
GlassFile        dummy_glass.dat            % File with unperturbed glass or
                                            % Cartesian grid
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TileFac          2                          % Number of times the glass file is
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                                            % tiled in each dimension (must be
                                            % an integer)


Omega            0.3089                     % Total matter density  (at z=0)
OmegaLambda      0.6911                     % Cosmological constant (at z=0)
OmegaBaryon      0.0                        % Baryon density        (at z=0)
HubbleParam      0.6774                     % Hubble paramater (may be used for power spec parameterization)
Redshift         127                        % Starting redshift
Sigma8           0.831                      % power spectrum normalization


SphereMode       1                          % if "1" only modes with |k| < k_Nyquist are
                                            % used (i.e. a sphere in k-space), otherwise modes with
                                            % |k_x|,|k_y|,|k_z| < k_Nyquist are used
                                            % (i.e. a cube in k-space)


WhichSpectrum    1                          % "1" selects Eisenstein & Hu spectrum,
                                            % "2" selects a tabulated power spectrum in
                                            % the file 'FileWithInputSpectrum'
                                            % otherwise, Efstathiou parametrization is used


FileWithInputSpectrum   input_spectrum.txt  % filename of tabulated input
                                            % spectrum (if used)
InputSpectrum_UnitLength_in_cm  3.085678e24 % defines length unit of tabulated
                                            % input spectrum in cm/h. 
                                            % Note: This can be chosen different from UnitLength_in_cm

ReNormalizeInputSpectrum   1                % if set to zero, the
                                            % tabulated spectrum is
                                            % assumed to be normalized
                                            % already in its amplitude to
                                            % the starting redshift,
                                            % otherwise this is recomputed
                                            % based on the specified sigma8


ShapeGamma       0.21                       % only needed for Efstathiou power spectrum 
PrimordialIndex  0.9645                     % may be used to tilt the primordial index, 
                                            % primordial spectrum is k^PrimordialIndex


Seed             123456                     %  seed for IC-generator


NumFilesWrittenInParallel 1                 % limits the number of files that are
                                            % written in parallel when outputting


UnitLength_in_cm          3.085678e21       % defines length unit of output (in cm/h) 
UnitMass_in_g             1.989e43          % defines mass unit of output (in g/cm)
UnitVelocity_in_cm_per_s  1e5               % defines velocity unit of output (in cm/sec)