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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <time.h>
  4. #include <complex>
  5.  
  6. using namespace std;
  7.  
  8. const int pp = 29;
  9. typedef complex<double> cdbl;
  10.  
  11. int main() {
  12. clock_t start = clock();
  13.   cdbl ff[pp], gg[pp];
  14.   for(int ii = 0; ii < pp; ii++) {
  15.     ff[ii] = gg[ii] = 1.0;
  16.   }
  17.  
  18.   for(int it = 0; it < 1000; it++) {
  19.     cdbl dual[pp];
  20.  
  21.     for(int ii = 0; ii < pp; ii++) {
  22.       dual[ii] = 0.0;
  23.     }
  24.  
  25.     for(int h1 = 0; h1 < pp; h1 ++) {
  26.       for(int h2 = 0; h2 < pp; h2 ++) {
  27.         cdbl avg_right = 0.0;
  28.         for(int xx = 0; xx < pp; xx ++) {
  29.           int c00 = xx, c01 = (xx + h1) % pp, c10 = (xx + h2) % pp, 
  30.               c11 = (xx + h1 + h2) % pp;
  31.           avg_right += ff[c00] * conj(ff[c01]) * conj(ff[c10]) * gg[c11];
  32.         }
  33.         avg_right /= static_cast<cdbl>(pp);
  34.  
  35.         for(int xx = 0; xx < pp; xx ++) {
  36.           int c01 = (xx + h1) % pp, c10 = (xx + h2) % pp, 
  37.               c11 = (xx + h1 + h2) % pp;
  38.           dual[xx] += conj(ff[c01]) * conj(ff[c10]) * ff[c11] * conj(avg_right);
  39.         }
  40.       }
  41.     }
  42.     for(int ii = 0; ii < pp; ii++) {
  43.       dual[ii] = conj(dual[ii]) / static_cast<double>(pp*pp);
  44.     }
  45.  
  46.     for(int ii = 0; ii < pp; ii++) {
  47.       gg[ii] = dual[ii];
  48.     }
  49.  
  50.  
  51.   }
  52.   printf("%.15lf\n", gg[0].real());
  53.   printf( "%lf\n" , ( double )( clock() - start ) / ( double )CLOCKS_PER_SEC );
  54.   return 0;
  55. }
Success #stdin #stdout 0.39s 15240KB
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Standard input is empty
stdout
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1.000000000000000
0.394447
https://ideone.com/DuAYHz
language:
C++14 (clang 8.0)
created:
8 years ago
visibility:
secret

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