add micro-benchmark for interaction forces.

Former-commit-id: e2c81502bc7bc66a2ab89194e59a39c5c0e6a0a0

examples/Makefile.am

@@ -25,7 +25,7 @@ AM_CFLAGS = -g -Wall -Werror -I../src $(OPENMP_CFLAGS) -DCPU_TPS=2.67e9
 AM_LDFLAGS =
 
 # Set-up the library
-bin_PROGRAMS = test test_fixed
+bin_PROGRAMS = test test_fixed test_single
 
 # Sources for test
 test_SOURCES = test.c
@@ -37,3 +37,8 @@ test_fixed_SOURCES = test.c
 test_fixed_CFLAGS = -DCOUNTER -DTIMER $(AM_CFLAGS) -DENGINE_POLICY="engine_policy_fixdt | engine_policy_keep"
 test_fixed_LDADD =  ../src/.libs/libswiftsim.a $(HDF5_LDFLAGS)
 
+# Sources for test_single
+test_single_SOURCES = test_single.c
+test_single_CFLAGS = -DCOUNTER -DTIMER $(AM_CFLAGS)
+test_single_LDADD =  ../src/.libs/libswiftsim.a $(HDF5_LDFLAGS)
+

examples/test_single.c

+/*******************************************************************************
+ * This file is part of SWIFT.
+ * Coypright (c) 2012 Pedro Gonnet (pedro.gonnet@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/>.
+ * 
+ ******************************************************************************/
+
+/* Config parameters. */
+#include "../config.h"
+
+/* Some standard headers. */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <pthread.h>
+#include <math.h>
+#include <float.h>
+#include <limits.h>
+#include <fenv.h>
+#include <omp.h>
+
+/* Conditional headers. */
+#ifdef HAVE_LIBZ
+    #include <zlib.h>
+#endif
+
+/* Local headers. */
+#include "swift.h"
+
+/* Ticks per second on this machine. */
+#ifndef CPU_TPS
+    #define CPU_TPS 2.67e9
+#endif
+
+/* Engine policy flags. */
+#ifndef ENGINE_POLICY
+    #define ENGINE_POLICY engine_policy_none
+#endif
+
+/* Error macro. */
+#define error(s) { printf( "%s:%s:%i: %s\n" , __FILE__ , __FUNCTION__ , __LINE__ , s ); abort(); }
+
+
+/**
+ * @brief Main routine that loads a few particles and generates some output.
+ *
+ */
+ 
+int main ( int argc , char *argv[] ) {
+
+    int k, N = 100;
+    struct part p1, p2;
+    float r2, dx[3] = { 0.0f , 0.0f , 0.0f };
+    
+    /* Init the particles. */
+    for ( k = 0 ; k < 3 ; k++ ) {
+        p1.a[k] = 0.0f; p1.v[k] = 0.0f; p1.x[k] = 0.0;
+        p2.a[k] = 0.0f; p2.v[k] = 0.0f; p2.x[k] = 0.0;
+        }
+    p1.rho = 1.0f; p1.mass = 9.7059e-4; p1.h = 0.222871287;
+    p2.rho = 1.0f; p2.mass = 9.7059e-4; p2.h = 0.222871287;
+    p1.force.c = 0.0f; p1.force.balsara = 0.0f;
+    p2.force.c = 0.0f; p2.force.balsara = 0.0f;
+    p1.u = 1.e-5 / ((const_gamma - 1.)*p1.rho);
+    p2.u = 1.e-5 / ((const_gamma - 1.)*p2.rho) + 100.0f / ( 33 * p2.mass );
+    p1.force.POrho2 = p1.u * ( const_gamma - 1.0f ) / p1.rho;
+    p2.force.POrho2 = p2.u * ( const_gamma - 1.0f ) / p2.rho;
+    
+    /* Dump a header. */
+    printf( "# r a_1 udt_1 a_2 udt_2\n" );
+    
+    /* Loop over the different radii. */
+    for ( k = 1 ; k <= N ; k++ ) {
+    
+        /* Set the distance/radius. */
+        dx[0] = -((float)k)/N * fmaxf( p1.h , p2.h );
+        r2 = dx[0]*dx[0];
+        
+        /* Clear the particle fields. */
+        p1.a[0] = 0.0f; p1.force.u_dt = 0.0f;
+        p2.a[0] = 0.0f; p2.force.u_dt = 0.0f;
+        
+        /* Interact the particles. */
+        runner_iact_force( r2 , dx , p1.h , p2.h , &p1 , &p2 );
+        
+        /* Output the results. */
+        printf( "%.3e %.3e %.3e %.3e %.3e\n" ,
+            -dx[0] , p1.a[0] , p1.force.u_dt , p2.a[0] , p2.force.u_dt );
+    
+        } /* loop over radii. */
+    
+    /* All is calm, all is bright. */
+    return 0;
+    
+    }