1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
#ifndef MARKOV_H
#define MARKOV_H
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <time.h>
extern int ITEMS;
extern double chain[][ITEM_CAP];
extern char item_names[][64];
void generate_chain(char *file_path)
{
FILE *fp = fopen(file_path, "r");
if(!fp) {
fprintf(stderr, "ERROR: Could not open file %s\n", file_path);
exit(EXIT_FAILURE);
}
int items_seen[ITEM_CAP][ITEM_CAP] = {0};
int cur_item = -1;
char line[256] = {0};
while((fgets(line, sizeof(line), fp)) != NULL)
{
if(line[strlen(line)-1] == '\n')
line[strlen(line)-1] = '\0';
int item = ITEMS;
for(int i = 0; i < ITEMS; i++)
{
if(strcmp(line, item_names[i]) == 0)
item = i;
}
if(item == ITEMS) {
ITEMS++;
strcpy(item_names[item], line);
}
if(cur_item != -1)
items_seen[cur_item][item]++;
cur_item = item;
}
fclose(fp);
for(int i = 0; i < ITEMS; i++)
{
int all = 0;
for(int j = 0; j < ITEMS; j++)
all += items_seen[i][j];
for(int j = 0; j < ITEMS; j++)
chain[i][j] = (double)items_seen[i][j]/all;
}
}
int walk_step(int item)
{
int item_lim = 0;
int r = rand();
for(int i = 0; i < ITEMS; i++)
{
item_lim += RAND_MAX * chain[item][i];
if(r <= item_lim) return i;
}
return -1;
}
void take_walk()
{
#ifdef SAVE_TO_FILE_ON_WALK
FILE *fp = fopen(SAVE_TO_FILE_ON_WALK, "w");
if(!fp) {
fprintf(stderr, "ERROR: Could not open file %s\n", SAVE_TO_FILE_ON_WALK);
exit(EXIT_FAILURE);
}
#endif
int items_seen[ITEM_CAP] = {0};
int cur_item = rand() % ITEMS;
for(size_t i = 0; i < WALK_LEN; i++)
{
#ifdef PRINT_ON_WALK
puts(item_names[cur_item]);
#endif
#ifdef SAVE_TO_FILE_ON_WALK
fprintf(fp, "%s\n", item_names[cur_item]);
#endif
items_seen[cur_item]++;
int ni = walk_step(cur_item);
assert(ni != -1);
cur_item = ni;
}
#ifdef SAVE_TO_FILE_ON_WALK
fclose(fp);
printf("Saved file with %d items at %s\n", WALK_LEN, SAVE_TO_FILE_ON_WALK);
#endif
#ifdef PRINT_ITEM_FREQUENCY
puts("Item Frequency:");
for(int i = 0; i < ITEMS; i++)
printf("%f %s\n", (double)items_seen[i]/WALK_LEN, item_names[i]);
puts("");
#endif
}
void print_chain()
{
puts("Chain Matrix:");
for(int i = 0; i < ITEMS; i++)
{
printf("{");
for(int j = 0; j < ITEMS; j++)
printf(" %f,", chain[i][j]);
printf("}\n");
}
puts("");
}
#endif
|
