diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000000000000000000000000000000000000..a728fcc60122906962df089fec66a26b9e5cf843
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,248 @@
+/**i @file main.c
+ *  @brief Code regarding input of parameters + starting of the code. */
+
+#include <stdlib.h>
+#include <time.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+//#include <getopt.h>
+#include <math.h>
+
+#include "cdr.h"
+#include "cstream.h"
+#include "grid.h"
+#include "parameters.h"
+#include "proto.h"
+#include "species.h"
+
+int main (int argc, char *argv[]);
+void start_process (cdr_grid_t *cdr);
+void output_tree (cdr_grid_t *cdr, int step, double t);
+void check_params (void);
+
+/** @brief The main program */
+int
+main (int argc, char *argv[])
+{
+  // param_t **p;
+  // char *s;
+  // struct option *opt;
+  // struct option *long_options;
+  // int c;
+  cdr_grid_t *cdr;
+  int count,count_user;
+  static const char *output_file;
+  config_t cfg,cfg_user;
+  config_setting_t *setting,*setting_user;
+  const char *prog_name,*f_defname,*f_username;
+
+  f_defname   = "input/default.cfg";
+  f_username  = "input/user_init.cfg";
+  output_file = "input/user_continue.cfg";
+  
+  /* Open configuration cfg */
+  config_init(&cfg);
+
+  /* Read the default file.
+   * The default file might be a result of a previous run, containing values
+   * for all global variables.
+   * If there is an error, report it and exit. */
+  if(! config_read_file(&cfg, f_defname))
+  {
+    fprintf(stderr, "%s:%d - %s\n", config_error_file(&cfg),
+            config_error_line(&cfg), config_error_text(&cfg));
+    config_destroy(&cfg);
+    return(EXIT_FAILURE);
+  }
+
+  /* Get the program name. */
+  if(config_lookup_string(&cfg, "name", &prog_name))
+    printf("Example : %s\n\n", prog_name);
+  else
+    fprintf(stderr, "No ' program name' setting in configuration file.\n");
+
+  /* Output a list of all parameters in the file. */
+  setting = config_lookup(&cfg, "param");
+  if(setting != NULL)
+  {
+    int i;
+    count = config_setting_length(setting);
+
+    fprintf(stdout, "# params: count=%i\n",count);
+
+    for(i = 0; i < count; ++i)
+    {
+      if (read_parameter(setting,setting,i,count,FALSE))
+        continue;
+    }
+
+    /* Write out the updated configuration. */
+    if(! config_write_file(&cfg, output_file))
+    {
+      fprintf(stderr, "Error while writing file.\n");
+      config_destroy(&cfg);
+      return(EXIT_FAILURE);
+    }
+    putchar('\n');
+  }
+  fprintf(stdout, "Default configuration successfully written to: %s\n",
+          output_file);
+
+/* ========================================================================== */
+ 
+  /* Open configuration cfg_user */
+  config_init(&cfg_user);
+
+  /* Read the file made by the user, with adapted values.
+   * This file does not have to contain entries for variables which remain
+   * unchanged.
+   * If there is an error, report it and exit. */
+  if(! config_read_file(&cfg_user, f_username))
+  {
+    fprintf(stderr, "%s:%d - %s\n", config_error_file(&cfg_user),
+            config_error_line(&cfg_user), config_error_text(&cfg_user));
+    config_destroy(&cfg_user);
+    return(EXIT_FAILURE);
+  }
+
+  /* Output a list of all parameters in the file. */
+  setting_user = config_lookup(&cfg_user, "param");
+  if(setting_user) 
+  {
+    int i;
+    count_user = config_setting_length(setting_user);
+
+    fprintf(stdout, "# params: count_user=%i\n",count_user);
+
+    for(i = 0; i < count_user; ++i)
+    {
+      if (read_parameter(setting,setting_user,i,count,TRUE))
+        continue;
+    }
+
+    /* Write out the updated configuration. */
+    if(! config_write_file(&cfg, output_file))
+    {
+      fprintf(stderr, "Error while writing file.\n");
+      config_destroy(&cfg);
+      return(EXIT_FAILURE);
+    } else {
+      fprintf(stdout, "Updated configuration successfully written to: %s\n",
+              output_file);
+    }
+    putchar('\n');
+  }
+
+  check_params ();
+
+  cstream_init ();
+
+  if (restart) {
+     if (0 == strcmp (load_file, "")) {
+       printf("restart file is empty\n");
+       return 1;
+     } else
+       cdr = cdr_load_tree_r (output_dir, load_file, NULL);
+  } else 
+    cdr = cdr_scratch_init ();
+
+  start_process(cdr);
+
+  /* Destroy both configurations */
+  config_destroy(&cfg_user);
+  config_destroy(&cfg);
+
+  return 0;
+}
+
+/** @brief Starts a given run on a given @a cdr tree. */
+void 
+start_process (cdr_grid_t *cdr)
+{ 
+  int i, i0;
+  double t, dt;
+  double t0, t1;
+  struct timeval tv;
+  FILE *fp;
+
+  i0 = (int) (start_t / output_dt);
+
+  debug(1,"before loop :start_t= %e; t = %e; dt = %e\n",start_t,t, dt);
+  /* This is the main loop of the code. */
+  for (i = i0, t = start_t; t < end_t; t += dt)
+    {
+      debug(1,"inside loop: i, t, dt : %d %e %e\n",i,t,dt);
+    /* Set the field and the fixed charge when we have time-dependent 
+       external fields (controled by rise_time) */
+      cstream_set_field_at_time (t);
+      dt = cdr_rk2 (cdr, attempt_dt, t);
+      cdr_update_refined (&cdr);
+      printf("t = %lf\tdt = %lf\tnext output at: %lf\n",t,dt,i * output_dt);
+      if (output_dt <= 0.0 || t >= output_dt * i) 
+	{
+	  output_tree (cdr, i, t);
+	  if (cdr->ntheta > 1) 
+	    {
+	      dft_out_weights (cdr, output_dir, t);
+	    }
+	  i++;
+	}
+    }
+  cdr_dump (cdr, output_dir, "C");
+  cdr_free_r (cdr);
+  cstream_end ();
+}
+
+/** @brief Outputs the tree contained in cdr.
+ *
+ * If pois_output (global parameter) is true, it also dumps the Poisson tree.
+ */
+void
+output_tree (cdr_grid_t *cdr, int step, double t)
+{
+  char *gname;
+  pois_grid_t **pois_modes;
+  FILE *fp;
+  char logfile[100];
+
+  asprintf (&gname, "C%.3d", step);
+  cdr_set_ext_bnd_r (cdr);
+
+  /* !!!!!!!!!!!! */
+  if (1 || t > start_t || 0 == strcmp (load_file, "")) {
+    cdr_dump_r (cdr, output_dir, gname, NULL, t);
+    cdr_dump_frames (cdr, output_dir, gname);
+
+    printf ("CDR grid %s saved\n", gname);
+  }
+
+  free (gname);
+
+  if (pois_output) {
+    int mode;
+    pois_modes = cdr_calc_field_r (cdr, TRUE);
+
+    for (mode = 0; mode < max_ntheta; mode++) {
+      asprintf (&gname, "P%.3d%.2d", step, mode);
+      pois_dump_r (pois_modes[mode], output_dir, gname);
+      pois_free_r (pois_modes[mode]);
+      printf ("Poisson grid %s saved\n", gname);
+      free (gname);
+    }
+
+    free (pois_modes);
+  }
+}
+
+/** @brief Checks for some errors in the parameters that will produce
+ *  nonsense output.
+ */
+void
+check_params ()
+{
+  if ((gridpoints_z % 4) != 0 && pois_inhom == 1) {
+    fatal ("To use inhomogeneous fields, gridpoints_z must be a"
+	   " multiple of 4\n");
+  }
+}