const.h 3.2 KB
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/*******************************************************************************
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 * This file is part of SWIFT.
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 * Coypright (c) 2012 Pedro Gonnet (pedro.gonnet@durham.ac.uk)
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 *                    Matthieu Schaller (matthieu.schaller@durham.ac.uk)
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 * 
 * 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/>.
 * 
 ******************************************************************************/


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/* Hydrodynamical constants. */
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#define const_hydro_gamma          (5.0f/3.0f)

/* SPH Viscosity constants. */
#define const_viscosity_alpha      0.8f            /* Used in the legacy gadget-2 SPH mode only */
#define const_viscosity_alpha_min  0.1f            /* Values taken from (Price,2004), not used in legacy gadget mode */
#define const_viscosity_alpha_max  2.0f            /* Values taken from (Price,2004), not used in legacy gadget mode */
#define const_viscosity_length     0.1f            /* Values taken from (Price,2004), not used in legacy gadget mode */

/* SPH Thermal conductivity constants. */
#define const_conductivity_alpha    1.f            /* Value taken from (Price,2008), not used in legacy gadget mode */
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/* Time integration constants. */
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#define const_cfl               0.3f
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#define const_ln_max_h_change   0.231111721f    /* Particle can't change volume by more than a factor of 2=1.26^3 over one time step */
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#define const_max_u_change      0.1f    
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/* Neighbour search constants. */
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#define const_eta_kernel        1.2349f         /* Corresponds to 48 ngbs with the cubic spline kernel */
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#define const_delta_nwneigh     1.f
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#define CUBIC_SPLINE_KERNEL
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/* Gravity stuff. */
#define const_theta_max         0.57735f        /* Opening criteria, which is the ratio of the
                                                   cell distance over the cell width. */
#define const_G                 6.67384e-8f     /* Gravitational constant. */
#define const_epsilon           0.0014f         /* Gravity blending distance. */
#define const_iepsilon          714.285714286f  /* Inverse gravity blending distance. */
#define const_iepsilon2         (const_iepsilon*const_iepsilon)
#define const_iepsilon3         (const_iepsilon2*const_iepsilon)
#define const_iepsilon4         (const_iepsilon2*const_iepsilon2)
#define const_iepsilon5         (const_iepsilon3*const_iepsilon2)
#define const_iepsilon6         (const_iepsilon3*const_iepsilon3)

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/* SPH variant to use */
#define LEGACY_GADGET2_SPH
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/* System of units */
#define const_unit_length_in_cgs       1 /* 3.08567810e16  /\* 1Mpc *\/ */
#define const_unit_mass_in_cgs         1 /* 1.9891e33      /\* 1 M_sun *\/ */
#define const_unit_velocity_in_cgs     1 /* 1e5            /\* km s^-1 *\/ */