tune_skin command.

src/core/tuning.cpp

@@ -26,6 +26,9 @@
 #include "utils.hpp"
 #include "communication.hpp"
 #include "errorhandling.hpp"
+#include "integrate.hpp"
+#include "global.hpp"
+#include <limits>
 
 int timing_samples = 0;
 
@@ -61,3 +64,44 @@ double time_force_calc(int default_samples)
   markTime();
   return diffTime()/rds;
 }
+
+static double time_calc(int rds)
+{
+  if (mpi_integrate(0, 0))
+    return -1;
+
+  /* perform force calculation test */
+  markTime();
+    if (mpi_integrate(rds, -1))
+      return -1;
+  markTime();
+  return diffTime()/rds;
+}
+
+
+void tune_skin(double min, double max, double tol) {
+  skin_set = true;
+
+  double a = min;
+  double b = max;
+  double time_a, time_b;
+
+  while(fabs(a - b) > tol) {
+    skin = a;
+    mpi_bcast_parameter(FIELD_SKIN);    
+    time_a = time_calc(1000);
+
+    skin = b;
+    mpi_bcast_parameter(FIELD_SKIN);    
+    time_b = time_calc(1000);
+
+    if(time_a > time_b) {
+      a = 0.5*(a + b);
+    } else {
+      b = 0.5*(a + b);
+    }
+    printf("a %e b %e time_a %e time_b %e delta %e\n", a, b, time_a, time_b, fabs(a - b));
+  }
+  skin = 0.5*(a+b);
+  mpi_bcast_parameter(FIELD_SKIN);    
+}

src/core/tuning.hpp

@@ -43,4 +43,8 @@ void markTime();
 /** calculate milliseconds between last two calls to \ref markTime. */
 double diffTime();
 
+/** sets the optimal \ref skin between min and max by bisectio to tolerance tol.
+ */
+void tune_skin(double min, double max, double tol);
+
 #endif

src/tcl/initialize_interpreter.cpp

@@ -122,6 +122,9 @@ char *get_default_scriptsdir();
 /** Returns runtime of the integration loop in seconds. From tuning_tcl.cpp **/
 int tclcommand_time_integration(ClientData data, Tcl_Interp *interp, int argc, char *argv[]);
 
+/** Tunes the skin */
+int tclcommand_tune_skin(ClientData data, Tcl_Interp *interp, int argc, char *argv[]);
+
 /** Reads particles from pdb file, see \ref readpdb.cpp */
 int tclcommand_readpdb(ClientData data, Tcl_Interp *interp, int argc, char *argv[]);
 
@@ -236,6 +239,7 @@ static void tcl_register_commands(Tcl_Interp* interp) {
   REGISTER_COMMAND("system_CMS_velocity", tclcommand_system_CMS_velocity);
   REGISTER_COMMAND("galilei_transform", tclcommand_galilei_transform);
   REGISTER_COMMAND("time_integration", tclcommand_time_integration);
+  REGISTER_COMMAND("tune_skin", tclcommand_tune_skin);
   REGISTER_COMMAND("electrokinetics", tclcommand_electrokinetics);
 #if defined(SD) || defined(BD)
   /* from integrate_sd_tcl.cpp */

src/tcl/tuning_tcl.cpp

@@ -55,3 +55,26 @@ int tclcommand_time_integration(ClientData data, Tcl_Interp *interp, int argc, c
   Tcl_AppendResult(interp, buffer, (char *)NULL);
   return TCL_OK;
 }
+
+int tclcommand_tune_skin(ClientData data, Tcl_Interp *interp, int argc, char *argv[]) {
+  if(argc != 4) {
+    puts("usage:");
+    return TCL_ERROR;
+  }
+
+  double min, max, tol;
+  if(!(ARG_IS_D(1, min) && ARG_IS_D(2, max) && ARG_IS_D(3, tol))) {
+    puts("usage:");
+    return TCL_ERROR;
+  }
+
+  tune_skin(min, max, tol);
+  return TCL_OK;
+}
+
+
+
+
+
+
+