Removed the softened isothermal potential. The isothermal potential is now...

Removed the softened isothermal potential. The isothermal potential is now softened by default. Set epsilon to 0 to restore the old behaviour.

configure.ac

@@ -766,9 +766,6 @@ case "$with_potential" in
    isothermal)
       AC_DEFINE([EXTERNAL_POTENTIAL_ISOTHERMAL], [1], [Isothermal external potential])
    ;; 
-   softened-isothermal)
-      AC_DEFINE([EXTERNAL_POTENTIAL_SOFTENED_ISOTHERMAL], [1], [Softened isothermal external potential])
-   ;; 
    disc-patch)
       AC_DEFINE([EXTERNAL_POTENTIAL_DISC_PATCH], [1], [Disc-patch external potential])
    ;; 

examples/CoolingHalo/cooling_halo.yml

@@ -37,7 +37,7 @@ InitialConditions:
   shift_z:    0.
  
 # External potential parameters
-SoftenedIsothermalPotential:
+IsothermalPotential:
   position_x:      0.     # location of centre of isothermal potential in internal units
   position_y:      0.
   position_z:      0.	

examples/CoolingHaloWithSpin/cooling_halo.yml

@@ -34,7 +34,7 @@ InitialConditions:
   file_name:  CoolingHalo.hdf5       # The file to read
  
 # External potential parameters
-SoftenedIsothermalPotential:
+IsothermalPotential:
   position_x:      0.     # location of centre of isothermal potential in internal units
   position_y:      0.
   position_z:      0.	

examples/HydrostaticHalo/hydrostatic.yml

@@ -34,7 +34,7 @@ InitialConditions:
   file_name:  Hydrostatic.hdf5       # The file to read
  
 # External potential parameters
-SoftenedIsothermalPotential:
+IsothermalPotential:
   position_x:      0.     # location of centre of isothermal potential in internal units
   position_y:      0.
   position_z:      0.	

examples/parameter_example.yml

@@ -81,15 +81,7 @@ IsothermalPotential:
   position_z:      100.
   vrot:            200.     # Rotation speed of isothermal potential (internal units)
   timestep_mult:   0.03     # Dimensionless pre-factor for the time-step condition
-
-# External potential parameters
-SoftenedIsothermalPotential:
-  position_x:      0.       # Location of centre of isothermal potential with respect to centre of the box (internal units)
-  position_y:      0.
-  position_z:      0.	
-  vrot:            200.     # rotation speed of isothermal potential (internal units)
   epsilon:         0.1      # Softening size (internal units)
-  timestep_mult:   0.03     # controls time step
   
 # Disk-patch potential parameters
 DiscPatchPotential:

src/Makefile.am

@@ -79,7 +79,6 @@ nobase_noinst_HEADERS = align.h approx_math.h atomic.h cycle.h error.h inline.h
 		 riemann/riemann_exact.h riemann/riemann_vacuum.h \
 	         potential/none/potential.h potential/point_mass/potential.h \
                  potential/isothermal/potential.h potential/disc_patch/potential.h \
-		 potential/softened_isothermal/potential.h \
 		 cooling/none/cooling.h cooling/none/cooling_struct.h \
 	         cooling/const_du/cooling.h cooling/const_du/cooling_struct.h \
                  cooling/const_lambda/cooling.h cooling/const_lambda/cooling_struct.h \

src/potential.h

@@ -34,8 +34,6 @@
 #include "./potential/point_mass/potential.h"
 #elif defined(EXTERNAL_POTENTIAL_ISOTHERMAL)
 #include "./potential/isothermal/potential.h"
-#elif defined(EXTERNAL_POTENTIAL_SOFTENED_ISOTHERMAL)
-#include "./potential/softened_isothermal/potential.h"
 #elif defined(EXTERNAL_POTENTIAL_DISC_PATCH)
 #include "./potential/disc_patch/potential.h"
 #else

src/potential/isothermal/potential.h

 /*******************************************************************************
  * This file is part of SWIFT.
- * Copyright (c) 2016 Tom Theuns (tom.theuns@durham.ac.uk)
- *                    Matthieu Schaller (matthieu.schaller@durham.ac.uk)
+ * Copyright (c) 2016  Tom Theuns (tom.theuns@durham.ac.uk)
+ *                     Stefan Arridge (stefan.arridge@durham.ac.uk)
+ *                     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
@@ -35,7 +36,8 @@
 #include "units.h"
 
 /**
- * @brief External Potential Properties - Isothermal sphere case
+ * @brief External Potential Properties - Isothermal sphere case with
+ * central softening
  */
 struct external_potential {
 
@@ -45,9 +47,14 @@ struct external_potential {
   /*! Rotation velocity */
   double vrot;
 
-  /*! Square of vrot divided by G \f$ \frac{v_{rot}^2}{G} \f$ */
+  /*! Square of vrot, the circular velocity which defines the isothermal
+   * potential devided by Newton's constant */
   double vrot2_over_G;
 
+  /*! Square of the softening length. Acceleration tends to zero within this
+   * distance from the origin */
+  double epsilon2;
+
   /*! Time-step condition pre-factor */
   double timestep_mult;
 };
@@ -70,17 +77,18 @@ __attribute__((always_inline)) INLINE static float external_gravity_timestep(
   const float dy = g->x[1] - potential->y;
   const float dz = g->x[2] - potential->z;
 
-  const float rinv2 = 1.f / (dx * dx + dy * dy + dz * dz);
+  const float r2_plus_epsilon2_inv =
+      1.f / (dx * dx + dy * dy + dz * dz + potential->epsilon2);
   const float drdv =
       dx * (g->v_full[0]) + dy * (g->v_full[1]) + dz * (g->v_full[2]);
   const double vrot = potential->vrot;
 
-  const float dota_x =
-      vrot * vrot * rinv2 * (g->v_full[0] - 2.f * drdv * dx * rinv2);
-  const float dota_y =
-      vrot * vrot * rinv2 * (g->v_full[1] - 2.f * drdv * dy * rinv2);
-  const float dota_z =
-      vrot * vrot * rinv2 * (g->v_full[2] - 2.f * drdv * dz * rinv2);
+  const float dota_x = vrot * vrot * r2_plus_epsilon2_inv *
+                       (g->v_full[0] - 2.f * drdv * dx * r2_plus_epsilon2_inv);
+  const float dota_y = vrot * vrot * r2_plus_epsilon2_inv *
+                       (g->v_full[1] - 2.f * drdv * dy * r2_plus_epsilon2_inv);
+  const float dota_z = vrot * vrot * r2_plus_epsilon2_inv *
+                       (g->v_full[2] - 2.f * drdv * dz * r2_plus_epsilon2_inv);
   const float dota_2 = dota_x * dota_x + dota_y * dota_y + dota_z * dota_z;
   const float a_2 = g->a_grav[0] * g->a_grav[0] + g->a_grav[1] * g->a_grav[1] +
                     g->a_grav[2] * g->a_grav[2];
@@ -94,6 +102,7 @@ __attribute__((always_inline)) INLINE static float external_gravity_timestep(
  * Note that the accelerations are multiplied by Newton's G constant
  * later on.
  *
+ * a = v_rot^2 * (x,y,z) / (r^2 + epsilon^2)
  * @param time The current time.
  * @param potential The #external_potential used in the run.
  * @param phys_const The physical constants in internal units.
@@ -106,10 +115,10 @@ __attribute__((always_inline)) INLINE static void external_gravity_acceleration(
   const float dx = g->x[0] - potential->x;
   const float dy = g->x[1] - potential->y;
   const float dz = g->x[2] - potential->z;
+  const float r2_plus_epsilon2_inv =
+      1.f / (dx * dx + dy * dy + dz * dz + potential->epsilon2);
 
-  const float rinv2 = 1.f / (dx * dx + dy * dy + dz * dz);
-
-  const double term = -potential->vrot2_over_G * rinv2;
+  const double term = -potential->vrot2_over_G * r2_plus_epsilon2_inv;
 
   g->a_grav[0] += term * dx;
   g->a_grav[1] += term * dy;
@@ -134,9 +143,8 @@ external_gravity_get_potential_energy(
   const float dz = g->x[2] - potential->z;
 
   return 0.5f * potential->vrot * potential->vrot *
-         logf(dx * dx + dy * dy * dz * dz);
+         logf(dx * dx + dy * dy * dz * dz + potential->epsilon2);
 }
-
 /**
  * @brief Initialises the external potential properties in the internal system
  * of units.
@@ -164,9 +172,11 @@ static INLINE void potential_init_backend(
       parser_get_param_double(parameter_file, "IsothermalPotential:vrot");
   potential->timestep_mult = parser_get_param_float(
       parameter_file, "IsothermalPotential:timestep_mult");
-
+  const double epsilon =
+      parser_get_param_double(parameter_file, "IsothermalPotential:epsilon");
   potential->vrot2_over_G =
       potential->vrot * potential->vrot / phys_const->const_newton_G;
+  potential->epsilon2 = epsilon * epsilon;
 }
 
 /**
@@ -180,9 +190,9 @@ static INLINE void potential_print_backend(
   message(
       "External potential is 'Isothermal' with properties are (x,y,z) = (%e, "
       "%e, %e), vrot = %e "
-      "timestep multiplier = %e.",
+      "timestep multiplier = %e, epsilon = %e",
       potential->x, potential->y, potential->z, potential->vrot,
-      potential->timestep_mult);
+      potential->timestep_mult, sqrtf(potential->epsilon2));
 }
 
-#endif /* SWIFT_POTENTIAL_ISOTHERMAL_H */
+#endif /* SWIFT_ISOTHERMAL_H */

src/potential/softened_isothermal/potential.h

-/*******************************************************************************
- * This file is part of SWIFT.
- * Copyright (c) 2016  Stefan Arridge (stefan.arridge@durham.ac.uk)
- *                     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_POTENTIAL_SOFTENED_ISOTHERMAL_H
-#define SWIFT_POTENTIAL_SOFTENED_ISOTHERMAL_H
-
-/* Config parameters. */
-#include "../config.h"
-
-/* Some standard headers. */
-#include <math.h>
-
-/* Local includes. */
-#include "error.h"
-#include "parser.h"
-#include "part.h"
-#include "physical_constants.h"
-#include "space.h"
-#include "units.h"
-
-/**
- * @brief External Potential Properties - Softened Isothermal sphere case
- */
-struct external_potential {
-
-  /*! Position of the centre of potential */
-  double x, y, z;
-
-  /*! Rotation velocity */
-  double vrot;
-
-  /*! Square of vrot, the circular velocity which defines the isothermal
-   * potential */
-  double vrot2_over_G;
-
-  /*! Square of the softening length. Acceleration tends to zero within this
-   * distance from the origin */
-  double epsilon2;
-
-  /*! Time-step condition pre-factor */
-  double timestep_mult;
-};
-
-/**
- * @brief Computes the time-step due to the acceleration from an isothermal
- * potential.
- *
- * @param time The current time.
- * @param potential The #external_potential used in the run.
- * @param phys_const The physical constants in internal units.
- * @param g Pointer to the g-particle data.
- */
-__attribute__((always_inline)) INLINE static float external_gravity_timestep(
-    double time, const struct external_potential* restrict potential,
-    const struct phys_const* restrict phys_const,
-    const struct gpart* restrict g) {
-
-  const float dx = g->x[0] - potential->x;
-  const float dy = g->x[1] - potential->y;
-  const float dz = g->x[2] - potential->z;
-
-  const float r2_plus_epsilon2_inv =
-      1.f / (dx * dx + dy * dy + dz * dz + potential->epsilon2);
-  const float drdv =
-      dx * (g->v_full[0]) + dy * (g->v_full[1]) + dz * (g->v_full[2]);
-  const double vrot = potential->vrot;
-
-  const float dota_x = vrot * vrot * r2_plus_epsilon2_inv *
-                       (g->v_full[0] - 2.f * drdv * dx * r2_plus_epsilon2_inv);
-  const float dota_y = vrot * vrot * r2_plus_epsilon2_inv *
-                       (g->v_full[1] - 2.f * drdv * dy * r2_plus_epsilon2_inv);
-  const float dota_z = vrot * vrot * r2_plus_epsilon2_inv *
-                       (g->v_full[2] - 2.f * drdv * dz * r2_plus_epsilon2_inv);
-  const float dota_2 = dota_x * dota_x + dota_y * dota_y + dota_z * dota_z;
-  const float a_2 = g->a_grav[0] * g->a_grav[0] + g->a_grav[1] * g->a_grav[1] +
-                    g->a_grav[2] * g->a_grav[2];
-
-  return potential->timestep_mult * sqrtf(a_2 / dota_2);
-}
-
-/**
- * @brief Computes the gravitational acceleration from an isothermal potential.
- *
- * Note that the accelerations are multiplied by Newton's G constant
- * later on.
- *
- * a = v_rot^2 * (x,y,z) / (r^2 + epsilon^2)
- * @param time The current time.
- * @param potential The #external_potential used in the run.
- * @param phys_const The physical constants in internal units.
- * @param g Pointer to the g-particle data.
- */
-__attribute__((always_inline)) INLINE static void external_gravity_acceleration(
-    double time, const struct external_potential* potential,
-    const struct phys_const* const phys_const, struct gpart* g) {
-
-  const float dx = g->x[0] - potential->x;
-  const float dy = g->x[1] - potential->y;
-  const float dz = g->x[2] - potential->z;
-  const float r2_plus_epsilon2_inv =
-      1.f / (dx * dx + dy * dy + dz * dz + potential->epsilon2);
-
-  const double term = -potential->vrot2_over_G * r2_plus_epsilon2_inv;
-
-  g->a_grav[0] += term * dx;
-  g->a_grav[1] += term * dy;
-  g->a_grav[2] += term * dz;
-}
-
-/**
- * @brief Computes the gravitational potential energy of a particle in an
- * isothermal potential.
- *
- * @param potential The #external_potential used in the run.
- * @param phys_const Physical constants in internal units.
- * @param g Pointer to the particle data.
- */
-__attribute__((always_inline)) INLINE static float
-external_gravity_get_potential_energy(
-    const struct external_potential* potential,
-    const struct phys_const* const phys_const, const struct gpart* g) {
-
-  const float dx = g->x[0] - potential->x;
-  const float dy = g->x[1] - potential->y;
-  const float dz = g->x[2] - potential->z;
-
-  return 0.5f * potential->vrot * potential->vrot *
-         logf(dx * dx + dy * dy * dz * dz + potential->epsilon2);
-}
-/**
- * @brief Initialises the external potential properties in the internal system
- * of units.
- *
- * @param parameter_file The parsed parameter file
- * @param phys_const Physical constants in internal units
- * @param us The current internal system of units
- * @param potential The external potential properties to initialize
- */
-static INLINE void potential_init_backend(
-    const struct swift_params* parameter_file,
-    const struct phys_const* phys_const, const struct UnitSystem* us,
-    const struct space* s, struct external_potential* potential) {
-
-  potential->x = s->dim[0] / 2. +
-                 parser_get_param_double(
-                     parameter_file, "SoftenedIsothermalPotential:position_x");
-  potential->y = s->dim[1] / 2. +
-                 parser_get_param_double(
-                     parameter_file, "SoftenedIsothermalPotential:position_y");
-  potential->z = s->dim[2] / 2. +
-                 parser_get_param_double(
-                     parameter_file, "SoftenedIsothermalPotential:position_z");
-  potential->vrot = parser_get_param_double(parameter_file,
-                                            "SoftenedIsothermalPotential:vrot");
-  potential->timestep_mult = parser_get_param_float(
-      parameter_file, "SoftenedIsothermalPotential:timestep_mult");
-  const double epsilon = parser_get_param_float(
-      parameter_file, "SoftenedIsothermalPotential:epsilon");
-  potential->vrot2_over_G =
-      potential->vrot * potential->vrot / phys_const->const_newton_G;
-  potential->epsilon2 = epsilon * epsilon;
-}
-
-/**
- * @brief Prints the properties of the external potential to stdout.
- *
- * @param  potential The external potential properties.
- */
-static INLINE void potential_print_backend(
-    const struct external_potential* potential) {
-
-  message(
-      "External potential is 'Isothermal' with properties are (x,y,z) = (%e, "
-      "%e, %e), vrot = %e "
-      "timestep multiplier = %e, epsilon = %e",
-      potential->x, potential->y, potential->z, potential->vrot,
-      potential->timestep_mult, sqrtf(potential->epsilon2));
-}
-
-#endif /* SWIFT_POTENTIAL_ISOTHERMAL_H */