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move time computation inside loop + comments

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Krishna Vedala 2020-04-02 13:26:54 -04:00
parent 3598708121
commit fa24b792a7
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GPG Key ID: BA19ACF8FC8792F7
1 changed files with 20 additions and 8 deletions
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28
project_euler/Problem 23/sol2.c
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@ -57,7 +57,7 @@ char get_perfect_number(unsigned long N)
char is_abundant(unsigned long N)
{
// return abundant_flags[N >> 3] & (1 << N % 8) ? 1 : 0;
return abundant_flags[N >> 3] & (1 << (N & 7)) ? 1 : 0;
return abundant_flags[N >> 3] & (1 << (N & 7)) ? 1 : 0; /* optimized modulo operation */
}
/**
@ -105,6 +105,11 @@ int main(int argc, char **argv)
* the flags are identified by bits
**/
abundant_flags = (char *)calloc(MAX_N >> 3, 1);
if (!abundant_flags)
{
perror("Unable to allocate memoey!");
return -1;
}
#ifdef _OPENMP
printf("Using OpenMP parallleization with %d threads\n", omp_get_max_threads());
@ -138,31 +143,38 @@ int main(int argc, char **argv)
double t1 = 1e3 * (end_time - start_time) / CLOCKS_PER_SEC;
printf("Time taken to get abundant numbers: %.4g ms\n", t1);
start_time = clock();
clock_t t2 = 0;
#ifdef _OPENMP
#pragma omp for schedule(runtime) private(start_time, end_time)
#endif
for (unsigned long i = 1; i < MAX_N; i++)
{
start_time = clock();
if (!is_sum_of_abundant(i))
#ifdef _OPENMP
#pragma omp critical
#endif
sum += i;
// if (i % 100 == 0)
// printf("... %5lu\n", i);
end_time = clock();
#ifdef _OPENMP
#pragma omp critical
#endif
t2 += end_time - start_time;
printf("... %5lu: %8lu\r", i, sum);
if (i % 100 == 0)
fflush(stdout);
}
end_time = clock();
#ifdef DEBUG
putchar('\n');
#endif
double t2 = 1e3 * (end_time - start_time) / CLOCKS_PER_SEC;
printf("Time taken for final sum: %.4g ms\nTotal Time taken: %.4g ms\n", t2, t1 + t2);
double t22 = 1e3 * t2 / CLOCKS_PER_SEC;
printf("Time taken for final sum: %.4g ms\nTotal Time taken: %.4g ms\n", t22, t1 + t22);
printf("Memory used: %lu bytes\n", MAX_N >> 3);
printf("Sum of numbers that cannot be represented as sum of two abundant numbers : %lu\n", sum);
free(abundant_flags);
// free(abundant_sum_flags);
return 0;
}