Add (placeholder for now) Tillotson equation of state

README_planetary

-SWIFT branch to add equations of state for planetary materials such as iron,
-silicate rocks, ices, and atmospheres; as well as allowing different particles
-to have different materials for the purpose of e.g. giant impact simulations.
+SWIFT 'planetary' branch
 
 Jacob Kegerreis
+
 jacob.kegerreis@durham.ac.uk
 
+# Aims:
+
++ Implement various equations of state, e.g. Tillotson, ANEOS
+
++ Allow multiple SPH materials with different EOS for different particles
+
++ Add examples, e.g. canonical Moon-forming giant impact
+
+# Status:
+
 

configure.ac

@@ -890,7 +890,7 @@ esac
 #  Equation of state
 AC_ARG_WITH([equation-of-state],
    [AS_HELP_STRING([--with-equation-of-state=<EoS>],
-      [equation of state @<:@ideal-gas, isothermal-gas default: ideal-gas@:>@]
+      [equation of state @<:@ideal-gas, isothermal-gas, tillotson-iron default: ideal-gas@:>@]
    )],
    [with_eos="$withval"],
    [with_eos="ideal-gas"]
@@ -902,6 +902,9 @@ case "$with_eos" in
    isothermal-gas)
       AC_DEFINE([EOS_ISOTHERMAL_GAS], [1], [Isothermal gas equation of state])
    ;;
+   tillotson-iron)
+      AC_DEFINE([EOS_TILLOTSON_IRON], [1], [Tillotson iron equation of state])
+   ;;
    *)
       AC_MSG_ERROR([Unknown equation of state: $with_eos])
    ;;

src/equation_of_state.h

@@ -34,6 +34,8 @@
 #include "./equation_of_state/ideal_gas/equation_of_state.h"
 #elif defined(EOS_ISOTHERMAL_GAS)
 #include "./equation_of_state/isothermal/equation_of_state.h"
+#elif defined(EOS_TILLOTSON_IRON)
+#include "./equation_of_state/tillotson_iron/equation_of_state.h"
 #else
 #error "Invalid choice of equation of state"
 #endif

src/equation_of_state/tillotson_iron/equation_of_state.h

+/*******************************************************************************
+ * This file is part of SWIFT.
+ * Copyright (c) 2016   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/>.
+ *
+ ******************************************************************************/
+#ifndef SWIFT_TILLOTSON_IRON_EQUATION_OF_STATE_H
+#define SWIFT_TILLOTSON_IRON_EQUATION_OF_STATE_H
+
+/* Some standard headers. */
+#include <math.h>
+
+/* Local headers. */
+#include "adiabatic_index.h"
+#include "common_io.h"
+#include "debug.h"
+#include "inline.h"
+
+extern struct eos_parameters eos;
+/* ------------------------------------------------------------------------- */
+
+struct eos_parameters {};
+
+/**
+ * @brief Returns the internal energy given density and entropy
+ *
+ * Computes \f$u = \frac{S\rho^{\gamma-1} }{\gamma - 1}\f$.
+ *
+ * @param density The density \f$\rho\f$.
+ * @param entropy The entropy \f$S\f$.
+ */
+__attribute__((always_inline)) INLINE static float
+gas_internal_energy_from_entropy(float density, float entropy) {
+
+  return entropy * pow_gamma_minus_one(density) *
+         hydro_one_over_gamma_minus_one;
+}
+
+/**
+ * @brief Returns the pressure given density and entropy
+ *
+ * Computes \f$P = S\rho^\gamma\f$.
+ *
+ * @param density The density \f$\rho\f$.
+ * @param entropy The entropy \f$S\f$.
+ */
+__attribute__((always_inline)) INLINE static float gas_pressure_from_entropy(
+    float density, float entropy) {
+
+  return entropy * pow_gamma(density);
+}
+
+/**
+ * @brief Returns the entropy given density and pressure.
+ *
+ * Computes \f$A = \frac{P}{\rho^\gamma}\f$.
+ *
+ * @param density The density \f$\rho\f$.
+ * @param pressure The pressure \f$P\f$.
+ * @return The entropy \f$A\f$.
+ */
+__attribute__((always_inline)) INLINE static float gas_entropy_from_pressure(
+    float density, float pressure) {
+
+  return pressure * pow_minus_gamma(density);
+}
+
+/**
+ * @brief Returns the sound speed given density and entropy
+ *
+ * Computes \f$c = \sqrt{\gamma S \rho^{\gamma-1}}\f$.
+ *
+ * @param density The density \f$\rho\f$.
+ * @param entropy The entropy \f$S\f$.
+ */
+__attribute__((always_inline)) INLINE static float gas_soundspeed_from_entropy(
+    float density, float entropy) {
+
+  return sqrtf(hydro_gamma * pow_gamma_minus_one(density) * entropy);
+}
+
+/**
+ * @brief Returns the entropy given density and internal energy
+ *
+ * Computes \f$S = \frac{(\gamma - 1)u}{\rho^{\gamma-1}}\f$.
+ *
+ * @param density The density \f$\rho\f$
+ * @param u The internal energy \f$u\f$
+ */
+__attribute__((always_inline)) INLINE static float
+gas_entropy_from_internal_energy(float density, float u) {
+
+  return hydro_gamma_minus_one * u * pow_minus_gamma_minus_one(density);
+}
+
+/**
+ * @brief Returns the pressure given density and internal energy
+ *
+ * Computes \f$P = (\gamma - 1)u\rho\f$.
+ *
+ * @param density The density \f$\rho\f$
+ * @param u The internal energy \f$u\f$
+ */
+__attribute__((always_inline)) INLINE static float
+gas_pressure_from_internal_energy(float density, float u) {
+
+  return hydro_gamma_minus_one * u * density;
+}
+
+/**
+ * @brief Returns the internal energy given density and pressure.
+ *
+ * Computes \f$u = \frac{1}{\gamma - 1}\frac{P}{\rho}\f$.
+ *
+ * @param density The density \f$\rho\f$.
+ * @param pressure The pressure \f$P\f$.
+ * @return The internal energy \f$u\f$.
+ */
+__attribute__((always_inline)) INLINE static float
+gas_internal_energy_from_pressure(float density, float pressure) {
+  return hydro_one_over_gamma_minus_one * pressure / density;
+}
+
+/**
+ * @brief Returns the sound speed given density and internal energy
+ *
+ * Computes \f$c = \sqrt{\gamma (\gamma - 1) u }\f$.
+ *
+ * @param density The density \f$\rho\f$
+ * @param u The internal energy \f$u\f$
+ */
+__attribute__((always_inline)) INLINE static float
+gas_soundspeed_from_internal_energy(float density, float u) {
+
+  return sqrtf(u * hydro_gamma * hydro_gamma_minus_one);
+}
+
+/**
+ * @brief Returns the sound speed given density and pressure
+ *
+ * Computes \f$c = \sqrt{\frac{\gamma P}{\rho} }\f$.
+ *
+ * @param density The density \f$\rho\f$
+ * @param P The pressure \f$P\f$
+ */
+__attribute__((always_inline)) INLINE static float gas_soundspeed_from_pressure(
+    float density, float P) {
+
+  const float density_inv = 1.f / density;
+  return sqrtf(hydro_gamma * P * density_inv);
+}
+
+/**
+ * @brief Initialize the eos parameters
+ *
+ * @param e The #eos_paramters
+ * @param params The parsed parameters
+ */
+__attribute__((always_inline)) INLINE static void eos_init(
+    struct eos_parameters *e, const struct swift_params *params) {}
+
+/**
+ * @brief Print the equation of state
+ *
+ * @param e The #eos_parameters
+ */
+__attribute__((always_inline)) INLINE static void eos_print(
+    const struct eos_parameters *e) {
+
+  message("Equation of state: Ideal gas.");
+
+  message("Adiabatic index gamma: %f.", hydro_gamma);
+}
+
+#if defined(HAVE_HDF5)
+/**
+ * @brief Write equation of state information to the snapshot
+ *
+ * @param h_grpsph The HDF5 group in which to write
+ * @param e The #eos_parameters
+ */
+__attribute__((always_inline)) INLINE static void eos_print_snapshot(
+    hid_t h_grpsph, const struct eos_parameters *e) {
+
+  io_write_attribute_f(h_grpsph, "Adiabatic index", hydro_gamma);
+
+  io_write_attribute_s(h_grpsph, "Equation of state", "Ideal gas");
+}
+#endif
+
+#endif /* SWIFT_TILLOTSON_IRON_EQUATION_OF_STATE_H */