1 #ifndef LIBCPP_TEST_VALARRAY_HELPER_H
2 #define LIBCPP_TEST_VALARRAY_HELPER_H
3 
4 #include <cmath>
5 
6 // Returns whether `x` and `y` are equal, up to the given number of
7 // significant digits after the decimal.
8 //
9 // Specifically, we look whether `abs(x - y) < epsilon`, where epsilon
10 // is `(1 / 10)^p`, assuming p is the number of digits we care about.
11 // This means we're basically looking whether `abs(x - y)` is less
12 // than `0.00..001` for some number of digits.
is_about(double x,double y,int significant_digits)13 inline bool is_about(double x, double y, int significant_digits) {
14     double epsilon = std::pow(1.0 / 10.0, significant_digits);
15     return std::abs(x - y) < epsilon;
16 }
17 
18 #endif /* LIBCPP_TEST_VALARRAY_HELPER */
19