/in/foo.cc: In function 'int main()':
/in/foo.cc:51:56: error: 'fabsl' is not a member of 'std'; did you mean 'fabs'?
   51 |                                 : w[j - k_best] * std::fabsl(sqrt_y[j] - sqrt_y[k_best]));
      |                                                        ^~~~~
      |                                                        fabs
/in/foo.cc:58:56: error: 'fabsl' is not a member of 'std'; did you mean 'fabs'?
   58 |                                     : w[j - k1] * std::fabsl(sqrt_y[j] - sqrt_y[k1]));
      |                                                        ^~~~~
      |                                                        fabs
/in/foo.cc:76:56: error: 'fabsl' is not a member of 'std'; did you mean 'fabs'?
   76 |                                 : w[k_best - j] * std::fabsl(sqrt_y[k_best] - sqrt_y[j]));
      |                                                        ^~~~~
      |                                                        fabs
/in/foo.cc:83:56: error: 'fabsl' is not a member of 'std'; did you mean 'fabs'?
   83 |                                     : w[k1 - j] * std::fabsl(sqrt_y[k1] - sqrt_y[j]));
      |                                                        ^~~~~
      |                                                        fabs