[160] | 1 | #include <stdio.h> |
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| 2 | #include <string.h> |
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| 3 | #include <math.h> |
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| 4 | #include <stdlib.h> |
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| 5 | #include <time.h> |
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| 6 | |
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| 7 | |
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| 8 | #include "Model.h" |
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| 9 | |
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| 10 | body* bodies; //vector that contains all the bodies in the system |
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| 11 | |
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| 12 | void setBody(body* b, double mass, double pos[3], double vel[3]){ |
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| 13 | |
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| 14 | b->mass = mass; |
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| 15 | memcpy(b->pos, pos, 3 * sizeof(double)); |
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| 16 | memcpy(b->vel, vel, 3 * sizeof(double)); |
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| 17 | } |
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| 18 | |
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| 19 | |
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| 20 | void initializeNBody(int n){ |
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| 21 | int i; |
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| 22 | double mass = 0; |
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| 23 | double pos[3] = {0, 0, 0}; |
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| 24 | double vel[3] = {0, 0, 0}; |
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| 25 | |
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| 26 | |
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| 27 | for (i = 0; i < n; i++){ |
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| 28 | setBody(&bodies[i], mass, pos, vel); |
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| 29 | //printf("%f %f\n", bodies[i].mass, bodies[i].pos[2]); |
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| 30 | } |
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| 31 | |
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| 32 | } |
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| 33 | |
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| 34 | //generate random float number between [low, high) |
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| 35 | double frand(double low, double high) |
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| 36 | { |
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| 37 | double temp; |
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| 38 | |
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| 39 | /* swap low & high around if the user makes no sense */ |
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| 40 | if (low > high){ |
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| 41 | temp = low; |
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| 42 | low = high; |
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| 43 | high = temp; |
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| 44 | } |
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| 45 | |
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| 46 | /* calculate the random number & return it */ |
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| 47 | temp = (rand() / ( RAND_MAX + 1.0)) |
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| 48 | * (high - low) + low; |
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| 49 | return temp; |
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| 50 | } |
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| 51 | |
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| 52 | |
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| 53 | |
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| 54 | void mkplummer(int n, unsigned int seed){ |
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| 55 | int i; |
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| 56 | double mass; |
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| 57 | double pos[3]; |
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| 58 | double vel[3]; |
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| 59 | double radius, theta, phi; |
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| 60 | double x, y; |
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| 61 | double velocity; |
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| 62 | |
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| 63 | if(seed == 0) |
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| 64 | srand(time(NULL)); //different succession of results in the subsequent calls to rand |
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| 65 | else srand(seed); //used for debugging |
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| 66 | |
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| 67 | initializeNBody(n); |
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| 68 | |
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| 69 | |
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| 70 | for(i = 0;i < n; i++){ |
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| 71 | mass = 1.0 / n; |
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| 72 | radius = 1.0 / sqrt(pow(frand(0, 1),-(2.0 / 3.0)) - 1.0); |
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| 73 | theta = acos(frand(-1, 1)); |
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| 74 | phi = frand(0, 2 * PI); |
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| 75 | pos[0] = radius * sin(theta) * cos(phi); |
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| 76 | pos[1] = radius * sin(theta) * sin(phi); |
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| 77 | pos[2] = radius * cos(theta); |
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| 78 | x = 0.0; |
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| 79 | y = 0.1; |
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| 80 | while( y > x * x * pow (1.0 - x*x, 3.5)){ |
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| 81 | x = frand(0, 1); |
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| 82 | y = frand(0, 0.1); |
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| 83 | } |
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| 84 | velocity = x * sqrt(2.0) * pow(1.0 + radius * radius, -0.25); |
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| 85 | theta = acos(frand(-1, 1)); |
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| 86 | phi = frand(0, 2 * PI); |
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| 87 | vel[0] = velocity * sin(theta) * cos(phi); |
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| 88 | vel[1] = velocity * sin(theta) * sin(phi); |
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| 89 | vel[2] = velocity * cos(theta); |
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| 90 | setBody(&bodies[i], mass, pos, vel); |
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| 91 | } |
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| 92 | |
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| 93 | |
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| 94 | |
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| 95 | } |
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| 96 | |
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| 97 | void writeData(int n){ |
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| 98 | char line[256]; |
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| 99 | int i; |
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| 100 | FILE *f = fopen(FILE_NAME, "w+"); |
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| 101 | if(f == NULL){ |
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| 102 | printf("Error opening file\n"); |
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| 103 | return; |
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| 104 | } |
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[164] | 105 | sprintf(line, "%d\n", n); |
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| 106 | fputs(line, f); |
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| 107 | sprintf(line, "%d\n", 0); |
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| 108 | fputs(line, f); |
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[160] | 109 | for(i = 0; i < n; i++){ |
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| 110 | //printf("here\n"); |
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| 111 | sprintf(line, "%f %f %f %f %f %f %f\n", |
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| 112 | bodies[i].mass, |
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| 113 | bodies[i].pos[0], bodies[i].pos[1], bodies[i].pos[2], |
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| 114 | bodies[i].vel[0], bodies[i].vel[1], bodies[i].vel[2]); |
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| 115 | fputs(line, f); |
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| 116 | } |
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| 117 | fclose(f); |
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| 118 | |
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| 119 | } |
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| 120 | |
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| 121 | int main(int argv, char** argc){ |
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| 122 | int n; |
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| 123 | unsigned int seed; |
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| 124 | if(argv != 3){ |
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| 125 | printf("usage ./Model nr_bodies seed\n"); |
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| 126 | return 0; |
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| 127 | } |
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| 128 | |
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| 129 | n = atoi(argc[1]); |
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| 130 | seed = atoi(argc[2]); |
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| 131 | |
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| 132 | bodies = (body*) malloc(n * sizeof(body)); |
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| 133 | mkplummer(n, seed); |
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| 134 | //writeData(n); |
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| 135 | return 1; |
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| 136 | } |
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