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simple bubble sorting of vectors (by their length). just for test
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| // to compile: | |
| // gcc -Wall -Wextra -O3 -funsafe-math-optimizations -o bubble-lab bubble-lab.c | |
| // or | |
| // gcc -Wall -Wextra -O3 -funsafe-math-optimizations -DCANNOT_RANDOM -o bubble-lab bubble-lab.c | |
| #include <stdlib.h> | |
| #include <stdio.h> | |
| #include <string.h> | |
| #ifndef CANNOT_RANDOM | |
| #include <sys/random.h> | |
| #endif | |
| #define VECTOR_SIZE 16 | |
| #define RANDOM_FLOAT_QUALITY 10 | |
| typedef float float_vector[VECTOR_SIZE]; | |
| #ifndef CANNOT_RANDOM | |
| static | |
| float | |
| getrandom_float () | |
| { | |
| float frnd = 0; | |
| for (int i = 0; i < RANDOM_FLOAT_QUALITY; ++i) | |
| { | |
| unsigned short rnd[4]; | |
| for (;;) | |
| { | |
| int rnd_len = getrandom (rnd, sizeof (rnd), 0); | |
| if (rnd_len != sizeof (rnd)) | |
| { | |
| if (rnd_len == -1) | |
| { | |
| fprintf(stderr, "failure getrandom()\n"); | |
| abort(); | |
| } | |
| fprintf(stderr, "retrying getrandom()\n"); | |
| continue; | |
| } | |
| break; | |
| } | |
| frnd += (float) rnd[0] / rnd[1]; | |
| frnd -= (float) rnd[2] / rnd[3]; | |
| } | |
| return frnd; | |
| } | |
| static int | |
| make_cmd (const char *out_path, const char *count_str) | |
| { | |
| int count = atoi (count_str); | |
| FILE *fout = fopen (out_path, "w"); | |
| if (!fout) | |
| { | |
| fprintf (stderr, "%s: failure opening file\n", out_path); | |
| return 1; | |
| } | |
| for (int i = 0; i < count; ++i) | |
| { | |
| for (int j = 0; j < VECTOR_SIZE; ++j) | |
| { | |
| float item = getrandom_float (); | |
| if (j) fputc (' ', fout); | |
| fprintf (fout, "%f", item); | |
| } | |
| fputc ('\n', fout); | |
| } | |
| fclose (fout); | |
| return 0; | |
| } | |
| #endif | |
| static inline float | |
| calculate_vec_len (float_vector vector) | |
| { | |
| float len = 0; | |
| for (int j = 0; j < VECTOR_SIZE; ++j) | |
| { | |
| len += vector[j] * vector[j]; | |
| } | |
| return len; | |
| } | |
| static int | |
| sort_cmd (const char *in_path, const char *out_path, const char *count_str, | |
| int noop) | |
| { | |
| int rv = 0; | |
| int count = atoi (count_str); | |
| float_vector *vectors = calloc (count, sizeof (float_vector)); | |
| FILE *fin = fopen (in_path, "r"); | |
| FILE *fout = fopen (out_path, "w"); | |
| if (!vectors) | |
| { | |
| fprintf (stderr, "%s: failure calloc()\n", in_path); | |
| rv = 1; | |
| goto out; | |
| } | |
| if (!fin) | |
| { | |
| fprintf (stderr, "%s: failure opening file\n", in_path); | |
| rv = 1; | |
| goto out; | |
| } | |
| if (!fout) | |
| { | |
| fprintf (stderr, "%s: failure opening file\n", out_path); | |
| rv = 1; | |
| goto out; | |
| } | |
| float_vector vector; | |
| int real_count = 0; | |
| for (int i = 0; i < count; ++i) | |
| { | |
| memset (vector, 0, sizeof (vector)); | |
| for (int j = 0; j < VECTOR_SIZE; ++j) | |
| { | |
| int scan_res = fscanf (fin, "%f", vector + j); | |
| if (scan_res == EOF) goto read_loop_out; | |
| } | |
| ++real_count; | |
| memcpy (vectors[i], vector, sizeof (vector)); | |
| } | |
| read_loop_out: | |
| if (!noop) | |
| { | |
| for (int i = 0; i < real_count - 1; ++i) | |
| { | |
| for (int k = i + 1; k < real_count; ++k) | |
| { | |
| float vec_i_len = calculate_vec_len (vectors[i]); | |
| float vec_k_len = calculate_vec_len (vectors[k]); | |
| if (vec_i_len > vec_k_len) | |
| { | |
| memcpy (vector, vectors[k], sizeof (vectors[k])); | |
| memcpy (vectors[k], vectors[i], sizeof (vectors[i])); | |
| memcpy (vectors[i], vector, sizeof (vector)); | |
| } | |
| } | |
| } | |
| } | |
| for (int i = 0; i < real_count; ++i) | |
| { | |
| //float vec_len = calculate_vec_len (vectors[i]); | |
| //fprintf (fout, "%f: ", vec_len); | |
| for (int j = 0; j < VECTOR_SIZE; ++j) | |
| { | |
| if (j) fputc (' ', fout); | |
| fprintf (fout, "%f", vectors[i][j]); | |
| } | |
| fputc ('\n', fout); | |
| } | |
| out: | |
| if (fout) fclose (fout); | |
| if (fin) fclose (fin); | |
| free (vectors); | |
| return rv; | |
| } | |
| int | |
| main (int argc, char *argv[]) | |
| { | |
| #ifndef CANNOT_RANDOM | |
| if (argc == 4 && !strcmp ("make", argv[1])) | |
| { | |
| return make_cmd (argv[2], argv[3]); | |
| } | |
| #endif | |
| if (argc == 5 && !strcmp ("sort", argv[1])) | |
| { | |
| return sort_cmd (argv[2], argv[3], argv[4], 0); | |
| } | |
| if (argc == 5 && !strcmp ("sort-noop", argv[1])) | |
| { | |
| return sort_cmd (argv[2], argv[3], argv[4], 1); | |
| } | |
| fprintf (stderr, "invalid args\n"); | |
| return 1; | |
| } | |
| // vi:ts=4:sw=4:et |
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