summaryrefslogtreecommitdiff
path: root/absl/random/internal/distribution_impl.h
diff options
context:
space:
mode:
authorGravatar Abseil Team <absl-team@google.com>2020-02-25 22:27:31 +0100
committerGravatar CJ Johnson <johnsoncj@google.com>2020-02-25 17:56:58 -0500
commitb832dce8489ef7b6231384909fd9b68d5a5ff2b7 (patch)
tree3ad4be9a9a4105366be714da9458e076a77be18f /absl/random/internal/distribution_impl.h
parentaa844899c937bde5d2b24f276b59997e5b668bde (diff)
Creation of LTS branch "lts_2020_02_25"20200225
- 0033c9ea91a52ade7c6b725aa2ef3cbe15463421 Fix build on FreeBSD/powerpc (#616) by kgotlinux <60880393+kgotlinux@users.noreply.github.com> - 0d5ce2797eb695aee7e019e25323251ef6ffc277 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - b69c7d880caddfc25bf348dbcfe9d45fdd8bc6e6 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 2a5633fc077a58528cdbfe78720f3f6bfdc6044d Merge "Export of internal Abseil changes" by Xiaoyi Zhang <zhangxy@google.com> - f9b3d6e493c1b6ab3dbdab71c5f8fa849db4abaf Add RISCV support to GetProgramCounter() (#621) by Khem Raj <raj.khem@gmail.com> - 0232c87f21c26718aa3eb2d86678070f3b498a4e Add missing ABSL_HAVE_VDSO_SUPPORT conditional (#622) by Sinan Kaya <41809318+franksinankaya@users.noreply.github.com> - 3c814105108680997d0821077694f663693b5382 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - c44657f55692eddf5504156645d1f4ec7b3acabd Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 98eb410c93ad059f9bba1bf43f5bb916fc92a5ea Export of internal Abseil changes by Abseil Team <absl-team@google.com> - bf78e977309c4cb946914b456404141ddac1c302 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - d95d1567165d449e4c213ea31a15cbb112a9865f Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 24713a7036a81498334807fa5c7ad3cb7c643711 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 72382c21fefed981b4b8a2a1b82e2d231c2c2e39 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 08a7e7bf972c8451855a5022f2faf3d3655db015 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 36bcd9599b3f48c99357ba61cf33584889306d6a Fix pointer format specifier in documentation (#614) by Andre Nguyen <andre-nguyen@users.noreply.github.com> - 0f86336b6939ea673cc1cbe29189286cae67d63a Export of internal Abseil changes by Abseil Team <absl-team@google.com> - c512f118dde6ffd51cb7d8ac8804bbaf4d266c3a Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 37dd2562ec830d547a1524bb306be313ac3f2556 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 44427702614d7b86b064ba06a390f5eb2f85dbf6 fix: Add support for more ARM processors detection (#608) by Andre Nguyen <andre-nguyen@users.noreply.github.com> - 159bf2bf6d1cc8087e02468d071e94d1177d1bae Export of internal Abseil changes by Abseil Team <absl-team@google.com> - a2e6adecc294dc4cd98cc285a9134ce58e0f2ad0 Use https links. (#586) by nlewycky <nicholas@mxc.ca> - 564001ae506a17c51fa1223684a78f05f91d3d91 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - b3aaac8a37c467a1125c794196caa90d0957bdc3 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 63ee2f8877915a3565c29707dba8fe4d7822596a Export of internal Abseil changes by Abseil Team <absl-team@google.com> - a048203a881f11f4b7b8df5fb563aec85522f8db Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 1de0166368e2ae67347f92099d6dca3ab3a4a496 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - ad904b6cd3906ddf79878003d92b7bc08d7786ae Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 29235139149790f5afc430c11cec8f1eb1677607 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - bf86cfe165ef7d70dfe68f0b8fc0c018bc79a577 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 12bc53e0318d80569270a5b26ccbc62b52022b89 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 1e39f8626a4dadec1f56920b999dd4c3cfae333e Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 77f87009a34c745255bd84d8f2647040d831a2b3 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - d659fe54b35ab9b8e35c72e50a4b8814167d5a84 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - a4b757b5d42694306a9de853cee0a5fba9c7bbe9 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 0514227d2547793b23e209809276375e41c76617 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 7f4fe64af80fe3c84db8ea938276c3690573c45e Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 16d9fd58a51c6083234e2e9f8f50e49ed5ed02e4 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - bcaae6009c0833b73c6fa7bdd972921d8081a724 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 8ba96a8244bbe334d09542e92d566673a65c1f78 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 2103fd9acdf58279f739860bff3f8c9f4b845605 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 3df7b52a6ada51a72a23796b844549a7b282f1b8 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - fa8c75182fbfdeddb2485fc0d53baeda3f40b7a3 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 85092b4b648ca729c6263c4a302a41dfff28705e Fix Conan builds (#400) by Adrian Ostrowski <adr.ostrowski@gmail.com> - e96ae2203b80d5ae2e0b7abe0c77b722b224b16d Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 20de2db748ca0471cfb61cb53e813dd12938c12b Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 846e5dbedac123d12455adcfe6f53c8b5dcbfeef Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 8207907f4f7fbaeeaa2b7340c76875e06fd345ba Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 078b89b3c046d230ef3ad39494e5852184eb528b Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 19b021cb3ff23048dfbe236a4e611925d8930831 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - ecc0033b54847f6c9ee37dbb0be8aa17e5b6d37b Always enable proper symbolize implementation on Windows ... by Loo Rong Jie <loorongjie@gmail.com> - 2796d500aea5a31d26b8b24a33fab7a1c8fa2f32 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - e4c8d0eb8ef4acb5d7a4252b3b87feb391ef7e41 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - a15364ce4d88534ae2295127e5d8e32aefb6b446 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - ab3552a18964e7063c8324f45b3896a6a20b08a8 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - e9f9000c7c80993cb589d011616b7a8016e42f4a Fix ABSL_WAITER_MODE detection for mingw (#342) by Joe Sylve <Joe.Sylve@gmail.com> - abea769b551f7a100f540967cb95debdb0080df8 Fix ABSL_HAVE_ALARM check on mingw (#341) by Joe Sylve <Joe.Sylve@gmail.com> - 25597bdfc148e91e27678ec30efa52f4fc8c164f Export of internal Abseil changes by Abseil Team <absl-team@google.com> - aad33fefaa8f744d71ce747a53717b835bdf8e84 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 8fe7214fe2d7a45ecc4d85f6a524c6b1532426de Export of internal Abseil changes by Abseil Team <absl-team@google.com> - debac94cfb5a0fa75d1d97c399682bd1c72e3191 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 882b3501a31eb0e4ae4213afb91a0e43feda7d5f Fix spelling errors (#384) by Sungmann Cho <55860394+chosungmann@users.noreply.github.com> - 502efe6d7841bff82b1aeef5500491fe9a48c635 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - ccdd1d57b6386ebc26fb0c7d99b604672437c124 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - ddf8e52a2918dd0ccec75d3e2426125fa3926724 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 6ec136281086b71da32b5fb068bd6e46b78a5c79 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - ac78ffc3bc0a8b295cab9a03817760fd460df2a1 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 5374c56e5196320681993869e3126b51edac2a43 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 97c1664b4bbab5f78fac2b151ab02656268fb34b Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 325fd7b042ff4ec34f7dd32e602cd81ad0e24b22 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 83c1d65c90a92aa49632b9ac5a793214bb0768bc Export of internal Abseil changes by Abseil Team <absl-team@google.com> - eb6b7bd23bc0815bfd784e1a74021ce166765280 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 9ddac555b7861dc178d0dbe758a1cfbed718784b Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 1948f6f967e34db9793cfa8b4bcbaf370d039fd8 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - a0d1e098c2f99694fa399b175a7ccf920762030e Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 2d2d7fbc283315b676159716376e739d3d23ed94 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 0302d1e5fa4fcdd1763b7d1bb3212943b1ae911d supppress unused variable warning for gcc (#372) by Martin <pizzard@users.noreply.github.com> - 262d74ba81b1fc4d71f459555cde8ecb39786d68 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - f0afae0d49af3e15a7169e019634d7719143d94d Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 0e7afdcbd24c7e5b7cab4e0217d8886f1525b520 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 9a41ffdd3a0ccbcdd29c4e3886b28e06f2cd9c66 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 36910d3d7e9fccadd6603f232d0c4f54dcd47c7e [bazel] Add fixes for --incompatible_load_cc_rules_from_b... by Yannic <contact@yannic-bonenberger.com> - aae8143cf9aa611f70d7ea9b95b8b8b383b2271a Export of internal Abseil changes by Abseil Team <absl-team@google.com> - d9aa92d7fb324314f9df487ac23d32a25650b742 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 321ab5303023c86cd15d9ddc5740fb4b4fde32e1 Export of internal Abseil changes by Abseil Team <absl-team@google.com> - 4ef574064e75b86f115549e9eb4c7e806781b3ab Export of internal Abseil changes by Abseil Team <absl-team@google.com> GitOrigin-RevId: 0033c9ea91a52ade7c6b725aa2ef3cbe15463421 Change-Id: I8a2b70063cb3ab40c6943a6db0fe40cae71ed8d7
Diffstat (limited to 'absl/random/internal/distribution_impl.h')
-rw-r--r--absl/random/internal/distribution_impl.h262
1 files changed, 0 insertions, 262 deletions
diff --git a/absl/random/internal/distribution_impl.h b/absl/random/internal/distribution_impl.h
deleted file mode 100644
index a8e5d61e..00000000
--- a/absl/random/internal/distribution_impl.h
+++ /dev/null
@@ -1,262 +0,0 @@
-// Copyright 2017 The Abseil Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef ABSL_RANDOM_INTERNAL_DISTRIBUTION_IMPL_H_
-#define ABSL_RANDOM_INTERNAL_DISTRIBUTION_IMPL_H_
-
-// This file contains some implementation details which are used by one or more
-// of the absl random number distributions.
-
-#include <cfloat>
-#include <cstddef>
-#include <cstdint>
-#include <cstring>
-#include <limits>
-#include <type_traits>
-
-#if (defined(_WIN32) || defined(_WIN64)) && defined(_M_IA64)
-#include <intrin.h> // NOLINT(build/include_order)
-#pragma intrinsic(_umul128)
-#define ABSL_INTERNAL_USE_UMUL128 1
-#endif
-
-#include "absl/base/config.h"
-#include "absl/base/internal/bits.h"
-#include "absl/numeric/int128.h"
-#include "absl/random/internal/fastmath.h"
-#include "absl/random/internal/traits.h"
-
-namespace absl {
-inline namespace lts_2019_08_08 {
-namespace random_internal {
-
-// Creates a double from `bits`, with the template fields controlling the
-// output.
-//
-// RandU64To is both more efficient and generates more unique values in the
-// result interval than known implementations of std::generate_canonical().
-//
-// The `Signed` parameter controls whether positive, negative, or both are
-// returned (thus affecting the output interval).
-// When Signed == SignedValueT, range is U(-1, 1)
-// When Signed == NegativeValueT, range is U(-1, 0)
-// When Signed == PositiveValueT, range is U(0, 1)
-//
-// When the `IncludeZero` parameter is true, the function may return 0 for some
-// inputs, otherwise it never returns 0.
-//
-// The `ExponentBias` parameter determines the scale of the output range by
-// adjusting the exponent.
-//
-// When a value in U(0,1) is required, use:
-// RandU64ToDouble<PositiveValueT, true, 0>();
-//
-// When a value in U(-1,1) is required, use:
-// RandU64ToDouble<SignedValueT, false, 0>() => U(-1, 1)
-// This generates more distinct values than the mathematically equivalent
-// expression `U(0, 1) * 2.0 - 1.0`, and is preferable.
-//
-// Scaling the result by powers of 2 (and avoiding a multiply) is also possible:
-// RandU64ToDouble<PositiveValueT, false, 1>(); => U(0, 2)
-// RandU64ToDouble<PositiveValueT, false, -1>(); => U(0, 0.5)
-//
-
-// Tristate types controlling the output.
-struct PositiveValueT {};
-struct NegativeValueT {};
-struct SignedValueT {};
-
-// RandU64ToDouble is the double-result variant of RandU64To, described above.
-template <typename Signed, bool IncludeZero, int ExponentBias = 0>
-inline double RandU64ToDouble(uint64_t bits) {
- static_assert(std::is_same<Signed, PositiveValueT>::value ||
- std::is_same<Signed, NegativeValueT>::value ||
- std::is_same<Signed, SignedValueT>::value,
- "");
-
- // Maybe use the left-most bit for a sign bit.
- uint64_t sign = std::is_same<Signed, NegativeValueT>::value
- ? 0x8000000000000000ull
- : 0; // Sign bits.
-
- if (std::is_same<Signed, SignedValueT>::value) {
- sign = bits & 0x8000000000000000ull;
- bits = bits & 0x7FFFFFFFFFFFFFFFull;
- }
- if (IncludeZero) {
- if (bits == 0u) return 0;
- }
-
- // Number of leading zeros is mapped to the exponent: 2^-clz
- int clz = base_internal::CountLeadingZeros64(bits);
- // Shift number left to erase leading zeros.
- bits <<= IncludeZero ? clz : (clz & 63);
-
- // Shift number right to remove bits that overflow double mantissa. The
- // direction of the shift depends on `clz`.
- bits >>= (64 - DBL_MANT_DIG);
-
- // Compute IEEE 754 double exponent.
- // In the Signed case, bits is a 63-bit number with a 0 msb. Adjust the
- // exponent to account for that.
- const uint64_t exp =
- (std::is_same<Signed, SignedValueT>::value ? 1023U : 1022U) +
- static_cast<uint64_t>(ExponentBias - clz);
- constexpr int kExp = DBL_MANT_DIG - 1;
- // Construct IEEE 754 double from exponent and mantissa.
- const uint64_t val = sign | (exp << kExp) | (bits & ((1ULL << kExp) - 1U));
-
- double res;
- static_assert(sizeof(res) == sizeof(val), "double is not 64 bit");
- // Memcpy value from "val" to "res" to avoid aliasing problems. Assumes that
- // endian-ness is same for double and uint64_t.
- std::memcpy(&res, &val, sizeof(res));
-
- return res;
-}
-
-// RandU64ToFloat is the float-result variant of RandU64To, described above.
-template <typename Signed, bool IncludeZero, int ExponentBias = 0>
-inline float RandU64ToFloat(uint64_t bits) {
- static_assert(std::is_same<Signed, PositiveValueT>::value ||
- std::is_same<Signed, NegativeValueT>::value ||
- std::is_same<Signed, SignedValueT>::value,
- "");
-
- // Maybe use the left-most bit for a sign bit.
- uint64_t sign = std::is_same<Signed, NegativeValueT>::value
- ? 0x80000000ul
- : 0; // Sign bits.
-
- if (std::is_same<Signed, SignedValueT>::value) {
- uint64_t a = bits & 0x8000000000000000ull;
- sign = static_cast<uint32_t>(a >> 32);
- bits = bits & 0x7FFFFFFFFFFFFFFFull;
- }
- if (IncludeZero) {
- if (bits == 0u) return 0;
- }
-
- // Number of leading zeros is mapped to the exponent: 2^-clz
- int clz = base_internal::CountLeadingZeros64(bits);
- // Shift number left to erase leading zeros.
- bits <<= IncludeZero ? clz : (clz & 63);
- // Shift number right to remove bits that overflow double mantissa. The
- // direction of the shift depends on `clz`.
- bits >>= (64 - FLT_MANT_DIG);
-
- // Construct IEEE 754 float exponent.
- // In the Signed case, bits is a 63-bit number with a 0 msb. Adjust the
- // exponent to account for that.
- const uint32_t exp =
- (std::is_same<Signed, SignedValueT>::value ? 127U : 126U) +
- static_cast<uint32_t>(ExponentBias - clz);
- constexpr int kExp = FLT_MANT_DIG - 1;
- const uint32_t val = sign | (exp << kExp) | (bits & ((1U << kExp) - 1U));
-
- float res;
- static_assert(sizeof(res) == sizeof(val), "float is not 32 bit");
- // Assumes that endian-ness is same for float and uint32_t.
- std::memcpy(&res, &val, sizeof(res));
-
- return res;
-}
-
-template <typename Result>
-struct RandU64ToReal {
- template <typename Signed, bool IncludeZero, int ExponentBias = 0>
- static inline Result Value(uint64_t bits) {
- return RandU64ToDouble<Signed, IncludeZero, ExponentBias>(bits);
- }
-};
-
-template <>
-struct RandU64ToReal<float> {
- template <typename Signed, bool IncludeZero, int ExponentBias = 0>
- static inline float Value(uint64_t bits) {
- return RandU64ToFloat<Signed, IncludeZero, ExponentBias>(bits);
- }
-};
-
-inline uint128 MultiplyU64ToU128(uint64_t a, uint64_t b) {
-#if defined(ABSL_HAVE_INTRINSIC_INT128)
- return uint128(static_cast<__uint128_t>(a) * b);
-#elif defined(ABSL_INTERNAL_USE_UMUL128)
- // uint64_t * uint64_t => uint128 multiply using imul intrinsic on MSVC.
- uint64_t high = 0;
- const uint64_t low = _umul128(a, b, &high);
- return absl::MakeUint128(high, low);
-#else
- // uint128(a) * uint128(b) in emulated mode computes a full 128-bit x 128-bit
- // multiply. However there are many cases where that is not necessary, and it
- // is only necessary to support a 64-bit x 64-bit = 128-bit multiply. This is
- // for those cases.
- const uint64_t a00 = static_cast<uint32_t>(a);
- const uint64_t a32 = a >> 32;
- const uint64_t b00 = static_cast<uint32_t>(b);
- const uint64_t b32 = b >> 32;
-
- const uint64_t c00 = a00 * b00;
- const uint64_t c32a = a00 * b32;
- const uint64_t c32b = a32 * b00;
- const uint64_t c64 = a32 * b32;
-
- const uint32_t carry =
- static_cast<uint32_t>(((c00 >> 32) + static_cast<uint32_t>(c32a) +
- static_cast<uint32_t>(c32b)) >>
- 32);
-
- return absl::MakeUint128(c64 + (c32a >> 32) + (c32b >> 32) + carry,
- c00 + (c32a << 32) + (c32b << 32));
-#endif
-}
-
-// wide_multiply<T> multiplies two N-bit values to a 2N-bit result.
-template <typename UIntType>
-struct wide_multiply {
- static constexpr size_t kN = std::numeric_limits<UIntType>::digits;
- using input_type = UIntType;
- using result_type = typename random_internal::unsigned_bits<kN * 2>::type;
-
- static result_type multiply(input_type a, input_type b) {
- return static_cast<result_type>(a) * b;
- }
-
- static input_type hi(result_type r) { return r >> kN; }
- static input_type lo(result_type r) { return r; }
-
- static_assert(std::is_unsigned<UIntType>::value,
- "Class-template wide_multiply<> argument must be unsigned.");
-};
-
-#ifndef ABSL_HAVE_INTRINSIC_INT128
-template <>
-struct wide_multiply<uint64_t> {
- using input_type = uint64_t;
- using result_type = uint128;
-
- static result_type multiply(uint64_t a, uint64_t b) {
- return MultiplyU64ToU128(a, b);
- }
-
- static uint64_t hi(result_type r) { return Uint128High64(r); }
- static uint64_t lo(result_type r) { return Uint128Low64(r); }
-};
-#endif
-
-} // namespace random_internal
-} // inline namespace lts_2019_08_08
-} // namespace absl
-
-#endif // ABSL_RANDOM_INTERNAL_DISTRIBUTION_IMPL_H_