wave_writer(char* file, int number_channels, int samples_per_sec) :
stream(file, file_stream::Writable),
data_size(0),
number_channels(number_channels),
samples_per_sec(samples_per_sec) {
write_header();
write_format();
start_data();
}
void verlet(cube &data_vector, double step_size, int time_steps, int n_planets, vec masses,double G,double epsilon){
mat accel(n_planets, 3);
mat start_data(n_planets,6);
accel.fill(0);
start_data.fill(0);
clock_t start,finish;
start = clock();
//Evolve through time
for(int t=0;t< time_steps-1;t++){
//Calculate inital acceleration
accel_calculate(data_vector,masses,n_planets,accel,t,G,epsilon);
for(int i=0; i<n_planets; i++){
for(int j=0; j <3; j++){
start_data(i,j) = data_vector(i,j,t);
start_data(i,j+3) = data_vector(i,j+3,t);
}
for(int j = 0; j<3; j++){
data_vector(i,j+3,t) = start_data(i,j+3) + 0.5*step_size*accel(i,j);
data_vector(i,j,t+1) = start_data(i,j) + step_size*start_data(i, j+3) + 0.5*step_size*step_size*accel(i,j);
}
}
accel_calculate(data_vector,masses,n_planets,accel,t,G,epsilon);
for(int i=0; i<n_planets; i++){
for(int j=0; j<3; j++){
data_vector(i,j+3,t) = data_vector(i, j+3,t) + 0.5*accel(i,j)*step_size;
}
}
//Update new position
for(int i=0; i<n_planets; i++){
for(int j=0; j<3; j++){
data_vector(i,j+3,t+1) = data_vector(i,j+3,t);
}
}
//Return start values
for(int i=0; i<n_planets; i++){
for(int j=0; j<3; j++){
data_vector(i,j,t) = start_data(i,j);
data_vector(i,j+3,t) = start_data(i,j+3);
}
}
}
finish = clock();
cout << "Total Velocity-Verlet time = "<< ((float)(finish-start)/CLOCKS_PER_SEC)<<" sec" << endl;
cout << "Velocity-Verlet time/step = "<< ((float)(finish-start)/CLOCKS_PER_SEC)/time_steps<<" sec" << endl;
}
void xm_from()
{
unsigned long data_size, rsrc_size;
char text[64];
if(receive_sync() == ACK) {
receive_part(info, DATABYTES, 1);
transname(info + I_NAMEOFF + 1, text, info[I_NAMEOFF]);
define_name(text);
data_size = get4(info + I_DLENOFF);
rsrc_size = get4(info + I_RLENOFF);
start_info(info, rsrc_size, data_size);
start_data();
receive_part(out_buffer, data_size, 1);
start_rsrc();
receive_part(out_buffer, rsrc_size, 0);
end_file();
}
}
void RK4_solve(cube &data_vector,double step_size,int time_steps, int n_planets,vec masses,double G,double epsilon){
//Define all the different variables used for the method
mat k1(n_planets,6);
mat k2(n_planets,6);
mat k3(n_planets,6);
mat k4(n_planets,6);
mat start_data(n_planets,6);
mat accel(n_planets,3);
k1.fill(0);
k2.fill(0);
k3.fill(0);
k4.fill(0);
start_data.fill(0);
accel.fill(0);
//Evolve through time
clock_t start,finish;
start = clock();
for(int t=0;t< time_steps-1;t++){
//Calculate inital acceleration
accel_calculate(data_vector,masses,n_planets,accel,t,G,epsilon);
for(int i=0;i< n_planets;i++){
//Set start data
for(int j=0;j<6;j++){
start_data(i,j) = data_vector(i,j,t);
//Calculate k1 for each dim
for(int j=0;j<3;j++){
k1(i,j)= step_size*data_vector(i,3+j,t);
k1(i,3+j)= step_size*accel(i,j);
}
}
//Save temp vel
for(int j=0;j<6;j++){
data_vector(i,j,t)= start_data(i,j) +k1(i,j)/2.;
}
}
//end k1 step
//Calculate new acceleration at this temporary position
accel_calculate(data_vector,masses,n_planets,accel,t,G,epsilon);
for(int i=0;i<n_planets;i++){
//Calculate k2 for each dim
k2(i,0)= step_size*data_vector(i,3,t);
k2(i,1)= step_size*data_vector(i,4,t);
k2(i,2)= step_size*data_vector(i,5,t);
k2(i,3)= step_size*accel(i,0);
k2(i,4)= step_size*accel(i,1);
k2(i,5)= step_size*accel(i,2);
//Save temp pos & temp vel
data_vector(i,0,t)= start_data(i,0) +k2(i,0)/2.;
data_vector(i,1,t)= start_data(i,1) +k2(i,1)/2.;
data_vector(i,2,t)= start_data(i,2) +k2(i,2)/2.;
data_vector(i,3,t)= start_data(i,3) +k2(i,3)/2.;
data_vector(i,4,t)= start_data(i,4) +k2(i,4)/2.;
data_vector(i,5,t)= start_data(i,5) +k2(i,5)/2.;
}
//Calculate new acceleration again
accel_calculate(data_vector,masses,n_planets,accel,t,G,epsilon);
for(int i=0;i<n_planets;i++){
//Calculate k3 for each dim
k3(i,0)= step_size*data_vector(i,3,t);
k3(i,1)= step_size*data_vector(i,4,t);
k3(i,2)= step_size*data_vector(i,5,t);
k3(i,3)= step_size*accel(i,0);
k3(i,4)= step_size*accel(i,1);
k3(i,5)= step_size*accel(i,2);
//Save temp vel and pos
data_vector(i,0,t)= start_data(i,0) +k3(i,0);
data_vector(i,1,t)= start_data(i,1) +k3(i,1);
data_vector(i,2,t)= start_data(i,2) +k3(i,2);
data_vector(i,3,t)= start_data(i,3) +k3(i,3);
data_vector(i,4,t)= start_data(i,4) +k3(i,4);
data_vector(i,5,t)= start_data(i,5) +k3(i,5);
}
//Calculate new acceleration again
accel_calculate(data_vector,masses,n_planets,accel,t,G,epsilon);
for(int i=0;i<n_planets;i++){
//Calculate k4 for each dim
k4(i,0)= step_size*data_vector(i,3,t);
k4(i,1)= step_size*data_vector(i,4,t);
k4(i,2)= step_size*data_vector(i,5,t);
k4(i,3)= step_size*accel(i,0);
k4(i,4)= step_size*accel(i,1);
k4(i,5)= step_size*accel(i,2);
//Return start position to data_vector
data_vector(i,0,t)= start_data(i,0);
data_vector(i,1,t)= start_data(i,1);
data_vector(i,2,t)= start_data(i,2);
data_vector(i,3,t)= start_data(i,3);
data_vector(i,4,t)= start_data(i,4);
data_vector(i,5,t)= start_data(i,5);
}
for(int i=0;i<n_planets;i++){
//Update new position
for(int j=0;j<6;j++){
data_vector(i,j,t+1) = data_vector(i,j,t) + 1/6.*(k1(i,j) + 2.*k2(i,j) + 2.*k3(i,j) + k4(i,j)); }
}
}
finish = clock();
cout << "Total RK4 time = "<< ((float)(finish-start)/CLOCKS_PER_SEC)<<" sec" << endl;
cout << "RK4 time/step = "<< ((float)(finish-start)/CLOCKS_PER_SEC)/time_steps<<" sec" << endl;
}
