Added example of a constant box evolving with cosmology.

examples/ConstantCosmoVolume/constant_volume.yml

+# Define the system of units to use internally. 
+InternalUnitSystem:
+  UnitMass_in_cgs:     1.98848e43    # 10^10 M_sun in grams
+  UnitLength_in_cgs:   3.08567758e24 # Mpc in centimeters
+  UnitVelocity_in_cgs: 1e5   # km/s in centimeters per second
+  UnitCurrent_in_cgs:  1   # Amperes
+  UnitTemp_in_cgs:     1   # Kelvin
+
+Cosmology:
+  Omega_m: 1.
+  Omega_lambda: 0.
+  Omega_b: 1.
+  h: 1.
+  a_begin: 0.00990099
+  a_end: 1.0
+
+# Parameters governing the time integration
+TimeIntegration:
+  dt_min:     1e-7  # The minimal time-step size of the simulation (in internal units).
+  dt_max:     5e-3  # The maximal time-step size of the simulation (in internal units).
+
+# Parameters governing the snapshots
+Snapshots:
+  basename:	       box      # Common part of the name of output files
+  time_first:          0.       # Time of the first output (in internal units)
+  delta_time:          1.04     # Time difference between consecutive outputs (in internal units)
+  scale_factor_first:  0.00991
+  compression:         4
+
+# Parameters governing the conserved quantities statistics
+Statistics:
+  delta_time:          2. # Time between statistics output
+
+# Parameters for the hydrodynamics scheme
+SPH:
+  resolution_eta:        1.2348   # Target smoothing length in units of the mean inter-particle separation 
+  CFL_condition:         0.1      # Courant-Friedrich-Levy condition for time integration.
+
+# Parameters related to the initial conditions
+InitialConditions:
+  file_name:  ./constantBox.hdf5       # The file to read
+
+Scheduler:
+  max_top_level_cells: 8
+  cell_split_size:     50
+  
+Gravity:
+  mesh_side_length:   32
+  eta: 0.025
+  theta: 0.3
+  r_cut_max: 5.
+  comoving_softening: 0.05
+  max_physical_softening: 0.05

examples/ConstantCosmoVolume/makeIC.py

+################################################################################
+# This file is part of SWIFT.
+# Copyright (c) 2018 Matthieu Schaller (matthieu.schaller@durham.ac.uk)
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published
+# by the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+################################################################################
+
+import h5py
+from numpy import *
+
+# Parameters
+T_i = 100.           # Initial temperature of the gas (in K)
+z_i = 100.           # Initial redshift
+gamma = 5./3.        # Gas adiabatic index
+numPart_1D = 32
+#glassFile = "glassCube_32.hdf5"
+fileName = "constantBox.hdf5"
+
+
+# Some units
+Mpc_in_m = 3.08567758e22
+Msol_in_kg = 1.98848e30
+Gyr_in_s = 3.08567758e19
+mH_in_kg = 1.6737236e-27
+
+# Some constants
+kB_in_SI = 1.38064852e-23
+G_in_SI = 6.67408e-11
+
+# Some useful variables in h-full units
+H_0 = 1. / Mpc_in_m * 10**5 # h s^-1
+rho_0 = 3. * H_0**2 / (8* math.pi * G_in_SI) # h^2 kg m^-3
+lambda_i = 64. / H_0 * 10**5 # h^-1 m (= 64 h^-1 Mpc)
+x_min = -0.5 * lambda_i
+x_max = 0.5 * lambda_i
+
+# SI system of units
+unit_l_in_si = Mpc_in_m
+unit_m_in_si = Msol_in_kg * 1.e10
+unit_t_in_si = Gyr_in_s
+unit_v_in_si = unit_l_in_si / unit_t_in_si
+unit_u_in_si = unit_v_in_si**2
+
+#---------------------------------------------------
+
+# Read the glass file
+#glass = h5py.File(glassFile, "r" )
+
+# Read particle positions and h from the glass
+#pos = glass["/PartType0/Coordinates"][:,:]
+#h = glass["/PartType0/SmoothingLength"][:] * 0.3
+#glass.close()
+
+# Total number of particles
+#numPart = size(h)
+#if numPart != numPart_1D**3:
+#  print "Non-matching glass file"
+numPart = numPart_1D**3
+
+# Set box size and interparticle distance
+boxSize = x_max - x_min
+delta_x = boxSize / numPart_1D
+
+# Get the particle mass
+a_i = 1. / (1. + z_i)
+m_i = boxSize**3 * rho_0 / numPart
+
+# Build the arrays
+#pos *= boxSize
+#h *= boxSize
+coords = zeros((numPart, 3))
+v = zeros((numPart, 3))
+ids = linspace(1, numPart, numPart)
+m = zeros(numPart)
+h = zeros(numPart)
+u = zeros(numPart)
+
+# Set the particles on the left
+for i in range(numPart_1D):
+  for j in range(numPart_1D):
+    for k in range(numPart_1D):
+      index = i * numPart_1D**2 + j * numPart_1D + k
+      coords[index,0] = (i + 0.5) * delta_x
+      coords[index,1] = (j + 0.5) * delta_x
+      coords[index,2] = (k + 0.5) * delta_x
+      u[index] = kB_in_SI * T_i / (gamma - 1.) / mH_in_kg
+      h[index] = 1.2348 * delta_x
+      m[index] = m_i
+      v[index,0] = 0.
+      v[index,1] = 0.
+      v[index,2] = 0.
+
+# Unit conversion
+coords /= unit_l_in_si
+v /= unit_v_in_si
+m /= unit_m_in_si
+h /= unit_l_in_si
+u /= unit_u_in_si
+
+boxSize /= unit_l_in_si
+
+#File
+file = h5py.File(fileName, 'w')
+
+# Header
+grp = file.create_group("/Header")
+grp.attrs["BoxSize"] = [boxSize, boxSize, boxSize]
+grp.attrs["NumPart_Total"] =  [numPart, 0, 0, 0, 0, 0]
+grp.attrs["NumPart_Total_HighWord"] = [0, 0, 0, 0, 0, 0]
+grp.attrs["NumPart_ThisFile"] = [numPart, 0, 0, 0, 0, 0]
+grp.attrs["Time"] = 0.0
+grp.attrs["NumFilesPerSnapshot"] = 1
+grp.attrs["MassTable"] = [0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
+grp.attrs["Flag_Entropy_ICs"] = 0
+grp.attrs["Dimension"] = 3
+
+#Runtime parameters
+grp = file.create_group("/RuntimePars")
+grp.attrs["PeriodicBoundariesOn"] = 1
+
+#Units
+grp = file.create_group("/Units")
+grp.attrs["Unit length in cgs (U_L)"] = 100. * unit_l_in_si
+grp.attrs["Unit mass in cgs (U_M)"] = 1000. * unit_m_in_si
+grp.attrs["Unit time in cgs (U_t)"] = 1. * unit_t_in_si
+grp.attrs["Unit current in cgs (U_I)"] = 1.
+grp.attrs["Unit temperature in cgs (U_T)"] = 1.
+
+#Particle group
+grp = file.create_group("/PartType0")
+grp.create_dataset('Coordinates', data=coords, dtype='d', compression="gzip", shuffle=True)
+grp.create_dataset('Velocities', data=v, dtype='f',compression="gzip", shuffle=True)
+grp.create_dataset('Masses', data=m, dtype='f', compression="gzip", shuffle=True)
+grp.create_dataset('SmoothingLength', data=h, dtype='f', compression="gzip", shuffle=True)
+grp.create_dataset('InternalEnergy', data=u, dtype='f', compression="gzip", shuffle=True)
+grp.create_dataset('ParticleIDs', data=ids, dtype='L', compression="gzip", shuffle=True)
+
+file.close()

examples/ConstantCosmoVolume/run.sh

+#!/bin/bash
+
+# Generate the initial conditions if they are not present.
+if [ ! -e constantBox.hdf5 ]
+then
+    echo "Generating initial conditions for the uniform cosmo box example..."
+    python makeIC.py
+fi
+
+# Run SWIFT
+../swift -s -c -G -t 8 constant_volume.yml 2>&1 | tee output.log
+
+# Plot the result
+python plotSolution.py $i

examples/ZeldovichPancake_3D/makeIC.py

@@ -146,7 +146,7 @@ grp.create_dataset('ParticleIDs', data=ids, dtype='L')
 
 file.close()
 
-import pylab as pl
+#import pylab as pl
 
-pl.plot(coords[:,0], v[:,0], "k.")
-pl.show()
+#pl.plot(coords[:,0], v[:,0], "k.")
+#pl.show()