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a Simple example std::sort at the end of make_list function. #2

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a Simple example std::sort at the end of make_list function. #2

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64 changes: 42 additions & 22 deletions MD/MD.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@
#include <vector>
#include <fstream>
#include <random>
//#include <algorithm>
#include <algorithm> // std::sort, etc..

namespace sim{
/* putting our stuff in its own namespace so we can call "time" "time"
Expand Down Expand Up @@ -58,13 +58,23 @@ int main(void){

int pnum = 100;
double box_length = 10, max_vel = 0.01;
double r = 0.1; // i have no clue what would be a good particle radius...

std::vector<Particle> curr_data = populate(pnum, box_length, max_vel);
std::vector<Interaction> inter_data = make_list(curr_data, box_length, r);

for (auto &p : curr_data){
// i tried to iterate through the sorted list
// All rtimes were NaN (not a number)
// I don't know much about physics so I'll leave it like that
// Sorting should work just like that though... Tested it with part1 (int)
// I tried without sorting, still all were NaN, so it's not that.
for (auto &i : inter_data){
//std::cout << i.part1 << std::endl;

std::cout << " x: " << curr_data[i.part1].pos_x <<
" y: " << curr_data[i.part1].pos_y <<
" z: " << curr_data[i.part1].pos_z << std::endl;

std::cout << p.pos_x << std::endl;

}

return 0;
Expand All @@ -85,9 +95,9 @@ std::vector<Particle> populate(int pnum, double box_length, double max_vel){
/* instead of doing % and * to get the correct distribution we directly
specify which distribution we want */

std::uniform_real_distribution<double>
std::uniform_real_distribution<double>
box_length_distribution(0, box_length);
std::uniform_real_distribution<double>
std::uniform_real_distribution<double>
max_vel_distribution(0, max_vel);

int PID_counter = 0;
Expand Down Expand Up @@ -115,26 +125,26 @@ std::vector<Interaction> make_list(const std::vector<Particle> &curr_data,
std::vector<Interaction> list;
Interaction test;
int i = 0,j = 0;
double del_x, del_y, del_z, del_vx, del_vy, del_vz, r_prime, rad_d;

// Step 1 -- find interactions
for (auto &ip : curr_data){
for (auto &jp : curr_data){
del_x = ip.pos_x - jp.pos_x;
del_y = ip.pos_y - jp.pos_y;
del_z = ip.pos_z - jp.pos_y;
double del_x = ip.pos_x - jp.pos_x;
double del_y = ip.pos_y - jp.pos_y;
double del_z = ip.pos_z - jp.pos_y;

del_vx = ip.vel_x - jp.vel_y;
del_vy = ip.vel_y - jp.vel_y;
del_vz = ip.vel_z - jp.vel_z;
double del_vx = ip.vel_x - jp.vel_y;
double del_vy = ip.vel_y - jp.vel_y;
double del_vz = ip.vel_z - jp.vel_z;

r_prime = 2 * radius;
double r_prime = 2 * radius;

rad_d = (pow(del_vx * del_x + del_vy * del_y
+ del_vz * del_z, 2)
- 4 * (del_vx * del_vx + del_vy * del_vy + del_vz * del_vz)
* (del_x * del_x + del_y * del_y + del_z * del_z
- r_prime * r_prime));
double rad_d = (pow(del_vx * del_x + del_vy * del_y
+ del_vz * del_z, 2)
- 4 * (del_vx * del_vx + del_vy * del_vy
+ del_vz * del_vz)
* (del_x * del_x + del_y * del_y + del_z * del_z
- r_prime * r_prime));

sim::time check;
if (del_x * del_vx >= 0 && del_y * del_vy >= 0 &&
Expand All @@ -147,7 +157,7 @@ std::vector<Interaction> make_list(const std::vector<Particle> &curr_data,
}

else {
check = (-(del_vx * del_x + del_vy * del_y + del_vz * del_z)
check = (-(del_vx * del_x + del_vy * del_y + del_vz * del_z)
+ sqrt(rad_d)) / (2 * (del_vx * del_vx + del_vz * del_vz
+ del_vy * del_vy));
}
Expand All @@ -166,14 +176,25 @@ std::vector<Interaction> make_list(const std::vector<Particle> &curr_data,
}

// Step 3 -- sort the list
// Our lambda expression acts as a rule for std::sort
// It will go through the list however the algorithm works
// And re-sort it so that lowest rtime is @ begin
// and highest @ end
// So it automatically makes those changes to input list
std::sort(list.begin(), list.end(),
[](const Interaction &il, const Interaction &ir)
{
return il.rtime < ir.rtime;
}
);
/*
// std::sort()
vector <Interaction> dummy;

for (auto &ele : list){
}

std::sort(std::begin(vec), std::end(vec), [](const Particle
std::sort(std::begin(vec), std::end(vec), [](const Particle
&lhs, const Particle &rhs){ return lhs.ts < rhs.ts; });
*/
return list;
Expand All @@ -186,4 +207,3 @@ void simulate(std::vector<int> interactions, std::vector<Particle> curr_data){


}