diff options
author | Vincent Ambo <mail@tazj.in> | 2020-11-21T13·43+0100 |
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committer | Vincent Ambo <mail@tazj.in> | 2020-11-21T14·48+0100 |
commit | 082c006c04343a78d87b6c6ab3608c25d6213c3f (patch) | |
tree | 16e6f04f8d1d1d2d67e8e917d5e7bb48c1b60375 /third_party/abseil_cpp/absl/random/internal/uniform_helper.h | |
parent | cc27324d0226953943f408ce3c69ad7d648e005e (diff) |
merge(3p/absl): subtree merge of Abseil up to e19260f r/1889
... notably, this includes Abseil's own StatusOr type, which conflicted with our implementation (that was taken from TensorFlow). Change-Id: Ie7d6764b64055caaeb8dc7b6b9d066291e6b538f
Diffstat (limited to '')
-rw-r--r-- | third_party/abseil_cpp/absl/random/internal/uniform_helper.h | 38 |
1 files changed, 36 insertions, 2 deletions
diff --git a/third_party/abseil_cpp/absl/random/internal/uniform_helper.h b/third_party/abseil_cpp/absl/random/internal/uniform_helper.h index 5b2afecb89e6..1243bc1c62ab 100644 --- a/third_party/abseil_cpp/absl/random/internal/uniform_helper.h +++ b/third_party/abseil_cpp/absl/random/internal/uniform_helper.h @@ -105,7 +105,7 @@ typename absl::enable_if_t< std::is_same<Tag, IntervalOpenOpenTag>>>::value, IntType> uniform_lower_bound(Tag, IntType a, IntType) { - return a + 1; + return a < (std::numeric_limits<IntType>::max)() ? (a + 1) : a; } template <typename FloatType, typename Tag> @@ -136,7 +136,7 @@ typename absl::enable_if_t< std::is_same<Tag, IntervalOpenOpenTag>>>::value, IntType> uniform_upper_bound(Tag, IntType, IntType b) { - return b - 1; + return b > (std::numeric_limits<IntType>::min)() ? (b - 1) : b; } template <typename FloatType, typename Tag> @@ -172,6 +172,40 @@ uniform_upper_bound(Tag, FloatType, FloatType b) { return std::nextafter(b, (std::numeric_limits<FloatType>::max)()); } +// Returns whether the bounds are valid for the underlying distribution. +// Inputs must have already been resolved via uniform_*_bound calls. +// +// The c++ standard constraints in [rand.dist.uni.int] are listed as: +// requires: lo <= hi. +// +// In the uniform_int_distrubtion, {lo, hi} are closed, closed. Thus: +// [0, 0] is legal. +// [0, 0) is not legal, but [0, 1) is, which translates to [0, 0]. +// (0, 1) is not legal, but (0, 2) is, which translates to [1, 1]. +// (0, 0] is not legal, but (0, 1] is, which translates to [1, 1]. +// +// The c++ standard constraints in [rand.dist.uni.real] are listed as: +// requires: lo <= hi. +// requires: (hi - lo) <= numeric_limits<T>::max() +// +// In the uniform_real_distribution, {lo, hi} are closed, open, Thus: +// [0, 0] is legal, which is [0, 0+epsilon). +// [0, 0) is legal. +// (0, 0) is not legal, but (0-epsilon, 0+epsilon) is. +// (0, 0] is not legal, but (0, 0+epsilon] is. +// +template <typename FloatType> +absl::enable_if_t<std::is_floating_point<FloatType>::value, bool> +is_uniform_range_valid(FloatType a, FloatType b) { + return a <= b && std::isfinite(b - a); +} + +template <typename IntType> +absl::enable_if_t<std::is_integral<IntType>::value, bool> +is_uniform_range_valid(IntType a, IntType b) { + return a <= b; +} + // UniformDistribution selects either absl::uniform_int_distribution // or absl::uniform_real_distribution depending on the NumType parameter. template <typename NumType> |