* @purpose N-Body simulator: declarations of simulation related parameters
*/
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <time.h>
+#include <sys/time.h> //POSIX time
+
+
+
#define SINGLE_THREADED
+// --- The below macros will be undefined by the multithreaded versions, and replaced with functions --- //
+
+//Sets up the simulation; in multithreaded versions, will spawn threads
+#define Simulation_Run(argc, argv) \
+if (options.draw_graphics) \
+ Graphics_Run(argc, argv); \
+else \
+{ \
+ while (ExitCondition() == false) \
+ { BeforeDraw(); AfterDraw(); } \
+}
+
+#define QuitProgram(error) (runstate = (error == true) ? QUIT : QUIT_ERROR) //Prepares to exit program, is thread safe in multithreaded versions
+
+//Macro to be overwritten in multithreaded versions, called before the graphics is allowed to draw anything
+#define BeforeDraw() \
+if (options.verbosity != 0 && universe.steps % options.verbosity == 0) \
+ DisplayStatistics(); \
+System_Compute(&universe);
+
+
+
+//Macro to be overwritten in multithreaded versions, called after the graphics has finished drawing.
+#define AfterDraw()
+
+// --- Constants and other Macros --- //
+
#define M_PI 3.14159265358979323846264338327950288 /* pi */
#define G 6.67428E-11
#define DELTA_T 0.05
#define DIMENSIONS 3
+#define LINE_SIZE 1000
#define square(x) ((x)*(x))
/**
* Structure to store an array of bodies, along with the size of the array.
- * The universe is represented in a single System.
+ * The universe is represented by a single System.
+ * In the multithreaded program, the universe is subdivided into one system for each working thread to use.
* @param N - Size of the array
* @param body - The array of bodies
*/
typedef struct
{
- unsigned N;
- Body * body;
+ unsigned N; // Number of bodies in the System
+ Body * body; // Array of bodies
+
+ unsigned steps; //Number of steps simulated
} System;
-void Body_Print(Body * a); //Print body a
+/**
+ * Structure to represent options passed to the program.
+ */
+typedef struct
+{
+ const char * input; // initial body field
+ const char * output; // file to write final positions / velocities of bodies to
+ const char * program; // program name
+ unsigned num_threads; // number of worker threads to spawn (must be greater than 1 for any to be spawned)
+ unsigned nested_threads; // number of threads to nest computations with (must be greater than 1 for any to be spawned)
+ unsigned num_steps; // number of steps to run before stopping (run indefinately if equal to zero)
+ unsigned timeout; // number of seconds to run before stopping (run indefinately if equal to zero)
+ bool draw_graphics; // whether or not to actually draw graphics
+ bool pedantic_graphics; // whether the graphics thread will synchronise with the computation thread (true) or just draw as fast as possible (false)
+ bool print_positions; // print positions of bodies to stdout on every step
+ unsigned verbosity; // print statistics every number of steps indicated by this variable
+ clock_t start_clock; // clock cycles done when simulation starts
+ struct timeval start_time; // time at which simulation starts
+} Options;
+
+void Body_Print(Body * a, FILE * out); //Print body a
void Body_Force(Body * a, System * s); //Compute force on body a due to system of bodies s
void Body_Velocity(Body * a); //Compute velocity of body a
void Body_Position(Body * a); //Compute position of body a
-void System_Init(System * s, char * fileName); //Initialise System (array of bodies) from a text file
+void System_Init(System * s, const char * fileName); //Initialise System (array of bodies) from a text file
+void System_Compute(System * s);
+void System_Forces(System * s1, System * s2); //Compute forces for bodies in s1 due to bodies in s2 (also updates velocities)
+void System_Positions(System * s); //Update positions for bodies in s1
+
+
+void Universe_Cleanup(); //Cleanup universe and write bodies to file
-void System_Compute(System * system); //Perform a single computation step for a System of bodies
+void DisplayStatistics(); // Print information about steps computed, total (real) runtime, and CPU cycles
-void Universe_Cleanup();
+
+bool ExitCondition(void); //Checks whether the program is supposed to exit automatically yet (ie: other than the user pressing "quit")
+
+
+typedef enum {RUN, QUIT, QUIT_ERROR} RUNSTATE;
+extern RUNSTATE runstate; // Set runstate to QUIT or QUIT_ERROR and the simulation will stop on the next step.
+// This is fairly redundant in the single threaded version, but useful for making sure *all* threads know to exit in the multi-threaded version
extern System universe; // The main array of bodies; global variable.
+extern Options options; // Parameters passed to program
+
+
#endif //_NBODY_H