/in/foo.cc: In function 'void Init()':
/in/foo.cc:42:19: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
    if(i & (1 << j - 1)) {
                 ~~^~~
/in/foo.cc:63:11: warning: unused variable 'b' [-Wunused-variable]
    double b = Gab(x[num[1]], y[num[1]], x[num[2]], y[num[2]]).second;
           ^