Created a test for symmetrical interaction functions.

tests/testSymInt.c

+/*******************************************************************************
+ * This file is part of SWIFT.
+ * Copyright (C) 2015 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/>.
+ *
+ ******************************************************************************/
+
+#include <fenv.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "swift.h"
+
+enum velocity_types {
+  velocity_zero,
+  velocity_random,
+  velocity_divergent,
+  velocity_rotating
+};
+
+char *serial_filename = "test_sym_serial.dat";
+char *vec_filename = "test_sym_vec.dat";
+
+/**
+ * @brief Constructs an array of particles in a valid state prior to
+ * a IACT_NONSYM and IACT_NONSYM_VEC call.
+ *
+ * @param count No. of particles to create
+ * @param offset The position of the particle offset from (0,0,0).
+ * @param spacing Particle spacing.
+ * @param h The smoothing length of the particles in units of the inter-particle
+ *separation.
+ * @param partId The running counter of IDs.
+ * @param vel The type of velocity field (0, random, divergent, rotating)
+ */
+struct part *make_particles(int count, double *offset, double spacing, double h, 
+                            long long *partId, enum velocity_types vel) {
+ 
+  struct part *particles;
+  if (posix_memalign((void **)&particles, part_align,
+                     count * sizeof(struct part)) != 0) {
+    error("couldn't allocate particles, no. of particles: %d", (int)count);
+  }
+   
+  /* Construct the particles */
+  struct part *p;
+  for (size_t i = 0; i < VEC_SIZE + 1; ++i) {
+    p = &particles[i];
+    p->x[0] = offset[0] + spacing * i;
+    p->x[1] = offset[1] + spacing * i;
+    p->x[2] = offset[2] + spacing * i;
+    switch (vel) {
+      case velocity_zero:
+        p->v[0] = 0.f;
+        p->v[1] = 0.f;
+        p->v[2] = 0.f;
+        break;
+      case velocity_random:
+        p->v[0] = random_uniform(-0.05, 0.05);
+        p->v[1] = random_uniform(-0.05, 0.05);
+        p->v[2] = random_uniform(-0.05, 0.05);
+        break;
+      case velocity_divergent:
+        p->v[0] = p->x[0] - 1.5 * spacing;
+        p->v[1] = p->x[1] - 1.5 * spacing;
+        p->v[2] = p->x[2] - 1.5 * spacing;
+        break;
+      case velocity_rotating:
+        p->v[0] = p->x[1];
+        p->v[1] = -p->x[0];
+        p->v[2] = 0.f;
+        break;
+    }
+    p->h = h;
+    p->id = ++(*partId);
+    p->mass = 1.0f;
+  }
+  return particles;
+}
+
+/**
+ * @brief Dumps all particle information to a file
+ */
+void dump_indv_particle_fields(char *fileName, struct part *p) {
+
+  FILE *file = fopen(fileName, "a");
+  
+  fprintf(
+      file,
+      "%6llu %10f %10f %10f %10f %10f %10f %13e %13e %13e %13e %13e "
+      "%13e %13e %13e\n",
+      p->id, p->x[0], p->x[1],
+      p->x[2], p->v[0], p->v[1],
+      p->v[2], p->rho, p->rho_dh,
+      p->density.wcount, p->density.wcount_dh,
+#ifdef GADGET2_SPH
+      p->div_v, p->density.rot_v[0],
+      p->density.rot_v[1], p->density.rot_v[2]
+#else
+      0., 0., 0., 0.
+#endif
+      );
+  fclose(file);
+}
+
+/**
+ * @brief Creates a header for the output file
+ */
+void write_header(char *fileName) {
+
+  FILE *file = fopen(fileName, "w");
+    /* Write header */
+    fprintf(file,
+            "# %4s %10s %10s %10s %10s %10s %10s %13s %13s %13s %13s %13s "
+            "%13s %13s %13s\n",
+            "ID", "pos_x", "pos_y", "pos_z", "v_x", "v_y", "v_z", "rho", "rho_dh",
+            "wcount", "wcount_dh", "div_v", "curl_vx", "curl_vy", "curl_vz");
+    fprintf(file,"\nPARTICLES BEFORE INTERACTION:\n");
+    fclose(file);
+}
+
+/*
+ * @brief Calls the serial and vectorised version of the non-symmetrical density interaction.
+ *
+ * @param parts Particle array to be interacted
+ * @param count No. of particles to be interacted
+ * 
+ */
+void test_sym_density_interaction(struct part *parts, int count) {
+  
+  /* Use the first particle in the array as the one that gets updated. */
+  struct part pi = parts[0];
+  //const float hig2 = hi * hi * kernel_gamma2;
+
+  FILE *file;
+  write_header(serial_filename);
+  write_header(vec_filename); 
+
+  /* Dump state of particles before serial interaction. */
+  dump_indv_particle_fields(serial_filename,&pi); 
+  for(size_t i = 1; i < count; i++)
+    dump_indv_particle_fields(serial_filename,&parts[i]); 
+
+  /* Make copy of pi to be used in vectorised version. */
+  struct part pi_vec = pi;
+  struct part pj_vec[VEC_SIZE];
+  for(int i=0; i<VEC_SIZE; i++)
+    pj_vec[i] = parts[i + 1];
+  
+  float r2q[VEC_SIZE] __attribute__((aligned(sizeof(float) * VEC_SIZE)));
+  float hiq[VEC_SIZE] __attribute__((aligned(sizeof(float) * VEC_SIZE)));
+  float hjq[VEC_SIZE] __attribute__((aligned(sizeof(float) * VEC_SIZE)));
+  float dxq[3 * VEC_SIZE] __attribute__((aligned(sizeof(float) * VEC_SIZE)));
+  struct part *piq[VEC_SIZE], *pjq[VEC_SIZE];
+  
+  /* Perform serial interaction */
+  for(int i=1; i<count; i++) {
+    /* Compute the pairwise distance. */
+    float r2 = 0.0f;
+    float dx[3];
+    for (int k = 0; k < 3; k++) {
+      dx[k] = pi.x[k] - parts[i].x[k];
+      r2 += dx[k] * dx[k];
+    }
+
+    runner_iact_density(r2, dx, pi.h, parts[i].h, &pi, &parts[i]);
+  }    
+
+  file = fopen(serial_filename, "a");
+  fprintf(file,"\nPARTICLES AFTER INTERACTION:\n");
+  fclose(file);
+
+  /* Dump result of serial interaction. */
+  dump_indv_particle_fields(serial_filename,&pi); 
+  for(size_t i = 1; i < count; i++)
+    dump_indv_particle_fields(serial_filename,&parts[i]); 
+
+  /* Setup arrays for vector interaction. */
+  for(int i=0; i<VEC_SIZE; i++) {
+    /* Compute the pairwise distance. */
+    float r2 = 0.0f;
+    float dx[3];
+    for (int k = 0; k < 3; k++) {
+      dx[k] = pi_vec.x[k] - pj_vec[i].x[k];
+      r2 += dx[k] * dx[k];
+    }
+    r2q[i] = r2;
+    dxq[3 * i + 0] = dx[0];
+    dxq[3 * i + 1] = dx[1];
+    dxq[3 * i + 2] = dx[2];
+    hiq[i] = pi_vec.h;
+    hjq[i] = pj_vec[i].h;
+    piq[i] = &pi_vec;
+    pjq[i] = &pj_vec[i];
+  }
+
+  /* Dump state of particles before vector interaction. */
+  dump_indv_particle_fields(vec_filename,piq[0]); 
+  for(size_t i = 0; i < VEC_SIZE; i++)
+    dump_indv_particle_fields(vec_filename,pjq[i]);
+  
+  /* Perform vector interaction. */
+  runner_iact_vec_density(r2q, dxq, hiq, hjq, piq, pjq);
+  
+  file = fopen(vec_filename, "a");
+  fprintf(file,"\nPARTICLES AFTER INTERACTION:\n");
+  fclose(file);
+  
+  /* Dump result of serial interaction. */
+  dump_indv_particle_fields(vec_filename,piq[0]); 
+  for(size_t i = 0; i < VEC_SIZE; i++)
+    dump_indv_particle_fields(vec_filename,pjq[i]);
+}
+
+/* And go... */
+int main(int argc, char *argv[]) {
+  double h = 1.2348, spacing = 0.5;
+  double offset[3] = {0.0,0.0,0.0};
+  int vel = velocity_zero;
+  int count = VEC_SIZE + 1;
+
+  /* Get some randomness going */
+  srand(0);
+
+  char c;
+  while ((c = getopt(argc, argv, "s:h:v:")) != -1) {
+    switch (c) {
+      case 'h':
+        sscanf(optarg, "%lf", &h);
+        break;
+      case 's':
+        sscanf(optarg, "%lf", &spacing);
+        break;
+      case 'v':
+        sscanf(optarg, "%d", &vel);
+        break;
+      case '?':
+        error("Unknown option.");
+        break;
+    }
+  }
+
+  if (h < 0 || spacing < 0) {
+    printf(
+        "\nUsage: %s [OPTIONS...]\n"
+        "\nGenerates a particle array with equal particle separation."
+        "\nThese are then interacted using runner_iact_density and runner_iact_vec_density."
+        "\n\nOptions:"
+        "\n-h DISTANCE=1.2348 - Smoothing length in units of <x>"
+        "\n-s spacing         - Spacing between particles"
+        "\n-v type (0,1,2,3)  - Velocity field: (zero, random, divergent, "
+        "rotating)",
+        argv[0]);
+    exit(1);
+  }
+  /* Help users... */
+  message("Smoothing length: h = %f", h);
+  message("Kernel:               %s", kernel_name);
+  message("Neighbour target: N = %f",
+          h * h * h * 4.0 * M_PI * kernel_gamma3 / 3.0);
+  message("div_v target:   div = %f", vel == 2 ? 3.f : 0.f);
+  message("curl_v target: curl = [0., 0., %f]", vel == 3 ? -2.f : 0.f);
+  printf("\n");
+
+  /* Build the infrastructure */
+  static long long partId = 0;
+  struct part *particles = make_particles(count,offset,spacing,h,&partId,vel);
+
+  /* Call the test non-sym density test. */
+  test_sym_density_interaction(particles,count);
+  
+  return 0;
+}