1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367
//! Utilities for Rust numbers.
//!
//! These traits define useful properties, methods, associated
//! types, and trait bounds, and conversions for working with
//! numbers in generic code.
#[cfg(feature = "f16")]
use crate::bf16::bf16;
#[cfg(feature = "f16")]
use crate::f16::f16;
use core::{fmt, mem, ops};
// AS PRIMITIVE
// ------------
/// Type that can be converted to primitive with `as`.
pub trait AsPrimitive: Copy + PartialEq + PartialOrd + Send + Sync + Sized {
fn as_u8(self) -> u8;
fn as_u16(self) -> u16;
fn as_u32(self) -> u32;
fn as_u64(self) -> u64;
fn as_u128(self) -> u128;
fn as_usize(self) -> usize;
fn as_i8(self) -> i8;
fn as_i16(self) -> i16;
fn as_i32(self) -> i32;
fn as_i64(self) -> i64;
fn as_i128(self) -> i128;
fn as_isize(self) -> isize;
fn as_f32(self) -> f32;
fn as_f64(self) -> f64;
fn from_u32(value: u32) -> Self;
#[cfg(feature = "f16")]
fn as_f16(self) -> f16;
#[cfg(feature = "f16")]
fn as_bf16(self) -> bf16;
}
macro_rules! as_primitive {
($($t:ty)*) => ($(
impl AsPrimitive for $t {
#[inline(always)]
fn as_u8(self) -> u8 {
self as _
}
#[inline(always)]
fn as_u16(self) -> u16 {
self as _
}
#[inline(always)]
fn as_u32(self) -> u32 {
self as _
}
#[inline(always)]
fn as_u64(self) -> u64 {
self as _
}
#[inline(always)]
fn as_u128(self) -> u128 {
self as _
}
#[inline(always)]
fn as_usize(self) -> usize {
self as _
}
#[inline(always)]
fn as_i8(self) -> i8 {
self as _
}
#[inline(always)]
fn as_i16(self) -> i16 {
self as _
}
#[inline(always)]
fn as_i32(self) -> i32 {
self as _
}
#[inline(always)]
fn as_i64(self) -> i64 {
self as _
}
#[inline(always)]
fn as_i128(self) -> i128 {
self as _
}
#[inline(always)]
fn as_isize(self) -> isize {
self as _
}
#[inline(always)]
fn as_f32(self) -> f32 {
self as _
}
#[inline(always)]
fn as_f64(self) -> f64 {
self as _
}
#[inline(always)]
fn from_u32(value: u32) -> Self {
value as _
}
#[cfg(feature = "f16")]
#[inline(always)]
fn as_f16(self) -> f16 {
f16::from_f32(self as f32)
}
#[cfg(feature = "f16")]
#[inline(always)]
fn as_bf16(self) -> bf16 {
bf16::from_f32(self as f32)
}
}
)*)
}
as_primitive! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize f32 f64 }
#[cfg(feature = "f16")]
macro_rules! half_as_primitive {
($($t:ty)*) => ($(
impl AsPrimitive for $t {
#[inline(always)]
fn as_u8(self) -> u8 {
self.as_f32() as _
}
#[inline(always)]
fn as_u16(self) -> u16 {
self.as_f32() as _
}
#[inline(always)]
fn as_u32(self) -> u32 {
self.as_f32() as _
}
#[inline(always)]
fn as_u64(self) -> u64 {
self.as_f32() as _
}
#[inline(always)]
fn as_u128(self) -> u128 {
self.as_f32() as _
}
#[inline(always)]
fn as_usize(self) -> usize {
self.as_f32() as _
}
#[inline(always)]
fn as_i8(self) -> i8 {
self.as_f32() as _
}
#[inline(always)]
fn as_i16(self) -> i16 {
self.as_f32() as _
}
#[inline(always)]
fn as_i32(self) -> i32 {
self.as_f32() as _
}
#[inline(always)]
fn as_i64(self) -> i64 {
self.as_f32() as _
}
#[inline(always)]
fn as_i128(self) -> i128 {
self.as_f32() as _
}
#[inline(always)]
fn as_isize(self) -> isize {
self.as_f32() as _
}
#[inline(always)]
fn as_f32(self) -> f32 {
self.as_f32() as _
}
#[inline(always)]
fn as_f64(self) -> f64 {
self.as_f32() as _
}
#[inline(always)]
fn from_u32(value: u32) -> Self {
Self::from_f32(value as _)
}
#[inline(always)]
fn as_f16(self) -> f16 {
f16::from_f32(self.as_f32())
}
#[inline(always)]
fn as_bf16(self) -> bf16 {
bf16::from_f32(self.as_f32())
}
}
)*)
}
#[cfg(feature = "f16")]
half_as_primitive! { f16 bf16 }
// AS CAST
// -------
/// An interface for casting between machine scalars.
pub trait AsCast: AsPrimitive {
/// Creates a number from another value that can be converted into
/// a primitive via the `AsPrimitive` trait.
fn as_cast<N: AsPrimitive>(n: N) -> Self;
}
/// Allows the high-level conversion of generic types as if `as` was used.
#[inline]
pub fn as_cast<U: AsCast, T: AsCast>(t: T) -> U {
U::as_cast(t)
}
macro_rules! as_cast {
($($t:ty, $meth:ident ; )*) => ($(
impl AsCast for $t {
#[inline]
fn as_cast<N: AsPrimitive>(n: N) -> $t {
n.$meth() as _
}
}
)*);
}
as_cast!(
u8, as_u8 ;
u16, as_u16 ;
u32, as_u32 ;
u64, as_u64 ;
u128, as_u128 ;
usize, as_usize ;
i8, as_i8 ;
i16, as_i16 ;
i32, as_i32 ;
i64, as_i64 ;
i128, as_i128 ;
isize, as_isize ;
f32, as_f32 ;
f64, as_f64 ;
);
#[cfg(feature = "f16")]
as_cast!(
f16, as_f16 ;
bf16, as_bf16 ;
);
// PRIMITIVE
// ---------
/// Primitive type trait (which all have static lifetimes).
pub trait Primitive: 'static + fmt::Debug + fmt::Display + AsCast {}
macro_rules! primitive {
($($t:ty)*) => ($(
impl Primitive for $t {}
)*)
}
primitive! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize f32 f64 }
#[cfg(feature = "f16")]
primitive! { f16 bf16 }
// NUMBER
// ------
/// Numerical type trait.
pub trait Number:
Default +
Primitive +
// Operations
ops::Add<Output=Self> +
ops::AddAssign +
ops::Div<Output=Self> +
ops::DivAssign +
ops::Mul<Output=Self> +
ops::MulAssign +
ops::Rem<Output=Self> +
ops::RemAssign +
ops::Sub<Output=Self> +
ops::SubAssign
{
/// If the number is a signed type.
const IS_SIGNED: bool;
}
macro_rules! number_impl {
($($t:tt $is_signed:literal ; )*) => ($(
impl Number for $t {
const IS_SIGNED: bool = $is_signed;
}
)*)
}
number_impl! {
u8 false ;
u16 false ;
u32 false ;
u64 false ;
u128 false ;
usize false ;
i8 true ;
i16 true ;
i32 true ;
i64 true ;
i128 true ;
isize true ;
f32 true ;
f64 true ;
// f128 true
}
#[cfg(feature = "f16")]
number_impl! {
f16 true ;
bf16 true ;
}
// INTEGER
// -------
/// Defines a trait that supports integral operations.
pub trait Integer:
// Basic
Number + Eq + Ord +
// Operations
ops::BitAnd<Output=Self> +
ops::BitAndAssign +
ops::BitOr<Output=Self> +
ops::BitOrAssign +
ops::BitXor<Output=Self> +
ops::BitXorAssign +
ops::Not<Output=Self> +
ops::Shl<Self, Output=Self> +
ops::Shl<i32, Output=Self> +
ops::ShlAssign<i32> +
ops::Shr<i32, Output=Self> +
ops::ShrAssign<i32> +
{
// CONSTANTS
const ZERO: Self;
const ONE: Self;
const TWO: Self;
const MAX: Self;
const MIN: Self;
const BITS: usize;
// FUNCTIONS (INHERITED)
fn leading_zeros(self) -> u32;
fn trailing_zeros(self) -> u32;
fn pow(self, exp: u32) -> Self;
fn checked_add(self, i: Self) -> Option<Self>;
fn checked_sub(self, i: Self) -> Option<Self>;
fn checked_mul(self, i: Self) -> Option<Self>;
fn overflowing_add(self, i: Self) -> (Self, bool);
fn overflowing_mul(self, i: Self) -> (Self, bool);
fn wrapping_add(self, i: Self) -> Self;
fn wrapping_sub(self, i: Self) -> Self;
fn wrapping_mul(self, i: Self) -> Self;
fn wrapping_neg(self) -> Self;
fn saturating_add(self, i: Self) -> Self;
fn saturating_sub(self, i: Self) -> Self;
fn saturating_mul(self, i: Self) -> Self;
/// Get the fast ceiling of the quotient from integer division.
/// Not safe, since the remainder can easily overflow.
#[inline]
fn ceil_divmod(self, y: Self) -> (Self, i32) {
let q = self / y;
let r = self % y;
match r == Self::ZERO {
true => (q, i32::as_cast(r)),
false => (q + Self::ONE, i32::as_cast(r) - i32::as_cast(y))
}
}
/// Get the fast ceiling of the quotient from integer division.
/// Not safe, since the remainder can easily overflow.
#[inline]
fn ceil_div(self, y: Self) -> Self {
self.ceil_divmod(y).0
}
/// Get the fast ceiling modulus from integer division.
/// Not safe, since the remainder can easily overflow.
#[inline]
fn ceil_mod(self, y: Self) -> i32 {
self.ceil_divmod(y).1
}
// PROPERTIES
/// Get the number of bits in a value.
#[inline]
fn bit_length(self) -> u32 {
Self::BITS as u32 - self.leading_zeros()
}
/// Returns true if the least-significant bit is odd.
#[inline]
fn is_odd(self) -> bool {
self & Self::ONE == Self::ONE
}
/// Returns true if the least-significant bit is even.
#[inline]
fn is_even(self) -> bool {
!self.is_odd()
}
}
macro_rules! integer_impl {
($($t:tt)*) => ($(
impl Integer for $t {
const ZERO: $t = 0;
const ONE: $t = 1;
const TWO: $t = 2;
const MAX: $t = $t::max_value();
const MIN: $t = $t::min_value();
// DEPRECATE: when we drop support for <= 1.53.0, change to `<$t>::BITS`
const BITS: usize = mem::size_of::<$t>() * 8;
#[inline]
fn leading_zeros(self) -> u32 {
$t::leading_zeros(self)
}
#[inline]
fn trailing_zeros(self) -> u32 {
$t::trailing_zeros(self)
}
#[inline]
fn checked_add(self, i: Self) -> Option<Self> {
$t::checked_add(self, i)
}
#[inline]
fn checked_sub(self, i: Self) -> Option<Self> {
$t::checked_sub(self, i)
}
#[inline]
fn checked_mul(self, i: Self) -> Option<Self> {
$t::checked_mul(self, i)
}
#[inline]
fn overflowing_add(self, i: Self) -> (Self, bool) {
$t::overflowing_add(self, i)
}
#[inline]
fn overflowing_mul(self, i: Self) -> (Self, bool) {
$t::overflowing_mul(self, i)
}
#[inline]
fn wrapping_add(self, i: Self) -> Self {
$t::wrapping_add(self, i)
}
#[inline]
fn wrapping_sub(self, i: Self) -> Self {
$t::wrapping_sub(self, i)
}
#[inline]
fn wrapping_mul(self, i: Self) -> Self {
$t::wrapping_mul(self, i)
}
#[inline]
fn wrapping_neg(self) -> Self {
$t::wrapping_neg(self)
}
#[inline]
fn pow(self, exp: u32) -> Self {
Self::pow(self, exp)
}
#[inline]
fn saturating_add(self, i: Self) -> Self {
$t::saturating_add(self, i)
}
#[inline]
fn saturating_sub(self, i: Self) -> Self {
$t::saturating_sub(self, i)
}
#[inline]
fn saturating_mul(self, i: Self) -> Self {
$t::saturating_mul(self, i)
}
}
)*)
}
integer_impl! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize }
// SIGNED INTEGER
// --------------
/// Defines a trait that supports signed integral operations.
pub trait SignedInteger: Integer + ops::Neg<Output = Self> {}
macro_rules! signed_integer_impl {
($($t:tt)*) => ($(
impl SignedInteger for $t {}
)*)
}
signed_integer_impl! { i8 i16 i32 i64 i128 isize }
// UNSIGNED INTEGER
// ----------------
/// Defines a trait that supports unsigned integral operations.
pub trait UnsignedInteger: Integer {}
macro_rules! unsigned_integer_impl {
($($t:ty)*) => ($(
impl UnsignedInteger for $t {}
)*)
}
unsigned_integer_impl! { u8 u16 u32 u64 u128 usize }
// FLOAT
// -----
/// Float information for native float types.
#[cfg(feature = "floats")]
pub trait Float: Number + ops::Neg<Output = Self> {
/// Unsigned type of the same size.
type Unsigned: UnsignedInteger;
// CONSTANTS
const ZERO: Self;
const ONE: Self;
const TWO: Self;
const MAX: Self;
const MIN: Self;
const INFINITY: Self;
const NEG_INFINITY: Self;
const NAN: Self;
const BITS: usize;
/// Bitmask for the sign bit.
const SIGN_MASK: Self::Unsigned;
/// Bitmask for the exponent, including the hidden bit.
const EXPONENT_MASK: Self::Unsigned;
/// Bitmask for the hidden bit in exponent, which is an implicit 1 in the fraction.
const HIDDEN_BIT_MASK: Self::Unsigned;
/// Bitmask for the mantissa (fraction), excluding the hidden bit.
const MANTISSA_MASK: Self::Unsigned;
/// Mask to determine if a full-carry occurred (1 in bit above hidden bit).
const CARRY_MASK: Self::Unsigned;
// PROPERTIES
// The following constants can be calculated as follows:
// - `INFINITY_BITS`: EXPONENT_MASK
// - `NEGATIVE_INFINITY_BITS`: INFINITY_BITS | SIGN_MASK
// - `EXPONENT_BIAS`: `2^(EXPONENT_SIZE-1) - 1 + MANTISSA_SIZE`
// - `DENORMAL_EXPONENT`: `1 - EXPONENT_BIAS`
// - `MAX_EXPONENT`: `2^EXPONENT_SIZE - 1 - EXPONENT_BIAS`
/// Positive infinity as bits.
const INFINITY_BITS: Self::Unsigned;
/// Positive infinity as bits.
const NEGATIVE_INFINITY_BITS: Self::Unsigned;
/// Size of the exponent.
const EXPONENT_SIZE: i32;
/// Size of the significand (mantissa) without hidden bit.
const MANTISSA_SIZE: i32;
/// Bias of the exponent.
const EXPONENT_BIAS: i32;
/// Exponent portion of a denormal float.
const DENORMAL_EXPONENT: i32;
/// Maximum exponent value in float.
const MAX_EXPONENT: i32;
// FUNCTIONS (INHERITED)
// Re-export the to and from bits methods.
fn to_bits(self) -> Self::Unsigned;
fn from_bits(u: Self::Unsigned) -> Self;
fn ln(self) -> Self;
fn floor(self) -> Self;
fn is_sign_positive(self) -> bool;
fn is_sign_negative(self) -> bool;
/// Returns true if the float is a denormal.
#[inline]
fn is_denormal(self) -> bool {
self.to_bits() & Self::EXPONENT_MASK == Self::Unsigned::ZERO
}
/// Returns true if the float is a NaN or Infinite.
#[inline]
fn is_special(self) -> bool {
self.to_bits() & Self::EXPONENT_MASK == Self::EXPONENT_MASK
}
/// Returns true if the float is NaN.
#[inline]
fn is_nan(self) -> bool {
self.is_special() && (self.to_bits() & Self::MANTISSA_MASK) != Self::Unsigned::ZERO
}
/// Returns true if the float is infinite.
#[inline]
fn is_inf(self) -> bool {
self.is_special() && (self.to_bits() & Self::MANTISSA_MASK) == Self::Unsigned::ZERO
}
/// Returns true if the float's least-significant mantissa bit is odd.
#[inline]
fn is_odd(self) -> bool {
self.to_bits().is_odd()
}
/// Returns true if the float's least-significant mantissa bit is even.
#[inline]
fn is_even(self) -> bool {
!self.is_odd()
}
/// Get exponent component from the float.
#[inline]
fn exponent(self) -> i32 {
if self.is_denormal() {
return Self::DENORMAL_EXPONENT;
}
let bits = self.to_bits();
let biased_e = i32::as_cast((bits & Self::EXPONENT_MASK) >> Self::MANTISSA_SIZE).as_i32();
biased_e - Self::EXPONENT_BIAS
}
/// Get mantissa (significand) component from float.
#[inline]
fn mantissa(self) -> Self::Unsigned {
let bits = self.to_bits();
let s = bits & Self::MANTISSA_MASK;
if !self.is_denormal() {
s + Self::HIDDEN_BIT_MASK
} else {
s
}
}
/// Get next greater float.
#[inline]
fn next(self) -> Self {
let bits = self.to_bits();
if self.is_sign_negative() && self == Self::ZERO {
// -0.0
Self::ZERO
} else if bits == Self::INFINITY_BITS {
Self::from_bits(Self::INFINITY_BITS)
} else if self.is_sign_negative() {
Self::from_bits(bits.saturating_sub(Self::Unsigned::ONE))
} else {
Self::from_bits(bits.saturating_add(Self::Unsigned::ONE))
}
}
/// Get next greater float for a positive float.
/// Value must be >= 0.0 and < INFINITY.
#[inline]
fn next_positive(self) -> Self {
debug_assert!(self.is_sign_positive() && !self.is_inf());
Self::from_bits(self.to_bits() + Self::Unsigned::ONE)
}
/// Get previous greater float, such that `self.prev().next() == self`.
#[inline]
fn prev(self) -> Self {
let bits = self.to_bits();
if self.is_sign_positive() && self == Self::ZERO {
// +0.0
-Self::ZERO
} else if bits == Self::NEGATIVE_INFINITY_BITS {
Self::from_bits(Self::NEGATIVE_INFINITY_BITS)
} else if self.is_sign_negative() {
Self::from_bits(bits.saturating_add(Self::Unsigned::ONE))
} else {
Self::from_bits(bits.saturating_sub(Self::Unsigned::ONE))
}
}
/// Get previous greater float for a positive float.
/// Value must be > 0.0.
#[inline]
fn prev_positive(self) -> Self {
debug_assert!(self.is_sign_positive() && self != Self::ZERO);
Self::from_bits(self.to_bits() - Self::Unsigned::ONE)
}
/// Round a positive number to even.
#[inline]
fn round_positive_even(self) -> Self {
if self.mantissa().is_odd() {
self.next_positive()
} else {
self
}
}
/// Get the max of two finite numbers.
#[inline]
fn max_finite(self, f: Self) -> Self {
debug_assert!(!self.is_special() && !f.is_special(), "max_finite self={} f={}", self, f);
if self < f {
f
} else {
self
}
}
/// Get the min of two finite numbers.
#[inline]
fn min_finite(self, f: Self) -> Self {
debug_assert!(!self.is_special() && !f.is_special(), "min_finite self={} f={}", self, f);
if self < f {
self
} else {
f
}
}
}
/// Define the float literals.
#[cfg(feature = "floats")]
macro_rules! float_literals {
($float:ty) => {
const ZERO: $float = 0.0;
const ONE: $float = 1.0;
const TWO: $float = 2.0;
const MAX: $float = <$float>::MAX;
const MIN: $float = <$float>::MIN;
const INFINITY: $float = <$float>::INFINITY;
const NEG_INFINITY: $float = <$float>::NEG_INFINITY;
const NAN: $float = <$float>::NAN;
const BITS: usize = mem::size_of::<$float>() * 8;
};
}
/// Define the float masks.
#[cfg(feature = "floats")]
macro_rules! float_masks {
(
float =>
$float:ty,sign_mask =>
$sign:literal,exponent_mask =>
$exponent:literal,hidden_bit_mask =>
$hidden:literal,mantissa_mask =>
$mantissa:literal,
) => {
const SIGN_MASK: <$float>::Unsigned = $sign;
const EXPONENT_MASK: <$float>::Unsigned = $exponent;
const HIDDEN_BIT_MASK: <$float>::Unsigned = $hidden;
const MANTISSA_MASK: <$float>::Unsigned = $mantissa;
// The carry mask is always 1 bit above the hidden bit.
const CARRY_MASK: <$float>::Unsigned = $hidden << 1;
// Infinity is always every exponent bit set.
const INFINITY_BITS: <$float>::Unsigned = $exponent;
// Negative infinity is just infinity + sign.
const NEGATIVE_INFINITY_BITS: <$float>::Unsigned = $exponent | $sign;
};
}
// Due to missing specifics or types for the following float types,
// `Float` is not yet fully implemented for:
// - f128
#[cfg(feature = "f16")]
macro_rules! float_one {
($f:ident) => {
(($f::EXPONENT_BIAS - $f::MANTISSA_SIZE) as u16) << $f::MANTISSA_SIZE
};
}
#[cfg(feature = "f16")]
macro_rules! float_two {
($f:ident) => {
(($f::EXPONENT_BIAS - $f::MANTISSA_SIZE + 1) as u16) << $f::MANTISSA_SIZE
};
}
#[cfg(feature = "f16")]
macro_rules! float_max {
($f:ident) => {
($f::EXPONENT_MASK ^ $f::HIDDEN_BIT_MASK) | $f::MANTISSA_MASK
};
}
#[cfg(feature = "f16")]
macro_rules! float_min {
($f:ident) => {
$f::MAX.to_bits() | $f::SIGN_MASK
};
}
#[cfg(feature = "f16")]
macro_rules! float_nan {
($f:ident) => {
$f::EXPONENT_MASK | ($f::HIDDEN_BIT_MASK >> 1)
};
}
#[cfg(feature = "f16")]
impl Float for f16 {
type Unsigned = u16;
const ZERO: Self = Self::from_bits(0);
const ONE: Self = Self::from_bits(float_one!(Self));
const TWO: Self = Self::from_bits(float_two!(Self));
const MAX: Self = Self::from_bits(float_max!(Self));
const MIN: Self = Self::from_bits(float_min!(Self));
const INFINITY: Self = Self::from_bits(Self::INFINITY_BITS);
const NEG_INFINITY: Self = Self::from_bits(Self::NEGATIVE_INFINITY_BITS);
const NAN: Self = Self::from_bits(float_nan!(Self));
const BITS: usize = mem::size_of::<Self>() * 8;
float_masks!(
float => Self,
sign_mask => 0x8000,
exponent_mask => 0x7C00,
hidden_bit_mask => 0x0400,
mantissa_mask => 0x03FF,
);
const EXPONENT_SIZE: i32 = 5;
const MANTISSA_SIZE: i32 = 10;
const EXPONENT_BIAS: i32 = 15 + Self::MANTISSA_SIZE;
const DENORMAL_EXPONENT: i32 = 1 - Self::EXPONENT_BIAS;
const MAX_EXPONENT: i32 = 0x1F - Self::EXPONENT_BIAS;
#[inline]
fn to_bits(self) -> u16 {
f16::to_bits(self)
}
#[inline]
fn from_bits(u: u16) -> f16 {
f16::from_bits(u)
}
#[inline]
fn ln(self) -> f16 {
f16::from_f32(self.as_f32().ln())
}
#[inline]
fn floor(self) -> f16 {
f16::from_f32(self.as_f32().floor())
}
#[inline]
fn is_sign_positive(self) -> bool {
self.to_bits() & Self::SIGN_MASK == 0
}
#[inline]
fn is_sign_negative(self) -> bool {
!self.is_sign_positive()
}
}
#[cfg(feature = "f16")]
impl Float for bf16 {
type Unsigned = u16;
const ZERO: Self = Self::from_bits(0);
const ONE: Self = Self::from_bits(float_one!(Self));
const TWO: Self = Self::from_bits(float_two!(Self));
const MAX: Self = Self::from_bits(float_max!(Self));
const MIN: Self = Self::from_bits(float_min!(Self));
const INFINITY: Self = Self::from_bits(Self::INFINITY_BITS);
const NEG_INFINITY: Self = Self::from_bits(Self::NEGATIVE_INFINITY_BITS);
const NAN: Self = Self::from_bits(float_nan!(Self));
const BITS: usize = mem::size_of::<Self>() * 8;
float_masks!(
float => Self,
sign_mask => 0x8000,
exponent_mask => 0x7F80,
hidden_bit_mask => 0x0080,
mantissa_mask => 0x007F,
);
const EXPONENT_SIZE: i32 = 8;
const MANTISSA_SIZE: i32 = 7;
const EXPONENT_BIAS: i32 = 127 + Self::MANTISSA_SIZE;
const DENORMAL_EXPONENT: i32 = 1 - Self::EXPONENT_BIAS;
const MAX_EXPONENT: i32 = 0xFF - Self::EXPONENT_BIAS;
#[inline]
fn to_bits(self) -> u16 {
bf16::to_bits(self)
}
#[inline]
fn from_bits(u: u16) -> bf16 {
bf16::from_bits(u)
}
#[inline]
fn ln(self) -> bf16 {
bf16::from_f32(self.as_f32().ln())
}
#[inline]
fn floor(self) -> bf16 {
bf16::from_f32(self.as_f32().floor())
}
#[inline]
fn is_sign_positive(self) -> bool {
self.to_bits() & Self::SIGN_MASK == 0
}
#[inline]
fn is_sign_negative(self) -> bool {
!self.is_sign_positive()
}
}
#[cfg(feature = "floats")]
impl Float for f32 {
type Unsigned = u32;
float_literals!(f32);
float_masks!(
float => Self,
sign_mask => 0x80000000,
exponent_mask => 0x7F800000,
hidden_bit_mask => 0x00800000,
mantissa_mask => 0x007FFFFF,
);
const EXPONENT_SIZE: i32 = 8;
const MANTISSA_SIZE: i32 = 23;
const EXPONENT_BIAS: i32 = 127 + Self::MANTISSA_SIZE;
const DENORMAL_EXPONENT: i32 = 1 - Self::EXPONENT_BIAS;
const MAX_EXPONENT: i32 = 0xFF - Self::EXPONENT_BIAS;
#[inline]
fn to_bits(self) -> u32 {
f32::to_bits(self)
}
#[inline]
fn from_bits(u: u32) -> f32 {
f32::from_bits(u)
}
#[inline]
fn ln(self) -> f32 {
#[cfg(feature = "std")]
return f32::ln(self);
#[cfg(not(feature = "std"))]
return logf(self);
}
#[inline]
fn floor(self) -> f32 {
#[cfg(feature = "std")]
return f32::floor(self);
#[cfg(not(feature = "std"))]
return floorf(self);
}
#[inline]
fn is_sign_positive(self) -> bool {
f32::is_sign_positive(self)
}
#[inline]
fn is_sign_negative(self) -> bool {
f32::is_sign_negative(self)
}
}
#[cfg(feature = "floats")]
impl Float for f64 {
type Unsigned = u64;
float_literals!(f64);
float_masks!(
float => Self,
sign_mask => 0x8000000000000000,
exponent_mask => 0x7FF0000000000000,
hidden_bit_mask => 0x0010000000000000,
mantissa_mask => 0x000FFFFFFFFFFFFF,
);
const EXPONENT_SIZE: i32 = 11;
const MANTISSA_SIZE: i32 = 52;
const EXPONENT_BIAS: i32 = 1023 + Self::MANTISSA_SIZE;
const DENORMAL_EXPONENT: i32 = 1 - Self::EXPONENT_BIAS;
const MAX_EXPONENT: i32 = 0x7FF - Self::EXPONENT_BIAS;
#[inline]
fn to_bits(self) -> u64 {
f64::to_bits(self)
}
#[inline]
fn from_bits(u: u64) -> f64 {
f64::from_bits(u)
}
#[inline]
fn ln(self) -> f64 {
#[cfg(feature = "std")]
return f64::ln(self);
#[cfg(not(feature = "std"))]
return logd(self);
}
#[inline]
fn floor(self) -> f64 {
#[cfg(feature = "std")]
return f64::floor(self);
#[cfg(not(feature = "std"))]
return floord(self);
}
#[inline]
fn is_sign_positive(self) -> bool {
f64::is_sign_positive(self)
}
#[inline]
fn is_sign_negative(self) -> bool {
f64::is_sign_negative(self)
}
}
// #[cfg(feature = "f128")]
// impl Float for f128 {
// type Unsigned = u128;
// float_literals!(f128);
// float_masks!(
// float => Self,
// sign_mask => 0x80000000000000000000000000000000,
// exponent_mask => 0x7FFF0000000000000000000000000000,
// hidden_bit_mask => 0x00010000000000000000000000000000,
// mantissa_mask => 0x0000FFFFFFFFFFFFFFFFFFFFFFFFFFFF,
// );
// const EXPONENT_SIZE: i32 = 15;
// const MANTISSA_SIZE: i32 = 112;
// const EXPONENT_BIAS: i32 = 16383 + Self::MANTISSA_SIZE;
// const DENORMAL_EXPONENT: i32 = 1 - Self::EXPONENT_BIAS;
// const MAX_EXPONENT: i32 = 0x7FFF - Self::EXPONENT_BIAS;
// }
// FLOAT HELPERS
// -------------
// These are adapted from libm, a port of musl libc's libm to Rust.
// libm can be found online [here](https://github.com/rust-lang/libm),
// and is similarly licensed under an Apache2.0/MIT license
/// # Safety
///
/// Safe as long as `e` is properly initialized.
#[cfg(all(not(feature = "std"), feature = "floats"))]
macro_rules! volatile {
($e:expr) => {
// SAFETY: safe as long as `$e` has been properly initialized.
unsafe {
core::ptr::read_volatile(&$e);
}
};
}
/// Floor (f64)
///
/// Finds the nearest integer less than or equal to `x`.
#[cfg(all(not(feature = "std"), feature = "floats"))]
fn floord(x: f64) -> f64 {
const TOINT: f64 = 1. / f64::EPSILON;
let ui = x.to_bits();
let e = ((ui >> 52) & 0x7ff) as i32;
if (e >= 0x3ff + 52) || (x == 0.) {
return x;
}
/* y = int(x) - x, where int(x) is an integer neighbor of x */
let y = if (ui >> 63) != 0 {
x - TOINT + TOINT - x
} else {
x + TOINT - TOINT - x
};
/* special case because of non-nearest rounding modes */
if e < 0x3ff {
volatile!(y);
return if (ui >> 63) != 0 {
-1.
} else {
0.
};
}
if y > 0. {
x + y - 1.
} else {
x + y
}
}
/// Floor (f32)
///
/// Finds the nearest integer less than or equal to `x`.
#[cfg(all(not(feature = "std"), feature = "floats"))]
fn floorf(x: f32) -> f32 {
let mut ui = x.to_bits();
let e = (((ui >> 23) as i32) & 0xff) - 0x7f;
if e >= 23 {
return x;
}
if e >= 0 {
let m: u32 = 0x007fffff >> e;
if (ui & m) == 0 {
return x;
}
volatile!(x + f32::from_bits(0x7b800000));
if ui >> 31 != 0 {
ui += m;
}
ui &= !m;
} else {
volatile!(x + f32::from_bits(0x7b800000));
if ui >> 31 == 0 {
ui = 0;
} else if ui << 1 != 0 {
return -1.0;
}
}
f32::from_bits(ui)
}
/* origin: FreeBSD /usr/src/lib/msun/src/e_log.c */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunSoft, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
/* log(x)
* Return the logarithm of x
*
* Method :
* 1. Argument Reduction: find k and f such that
* x = 2^k * (1+f),
* where sqrt(2)/2 < 1+f < sqrt(2) .
*
* 2. Approximation of log(1+f).
* Let s = f/(2+f) ; based on log(1+f) = log(1+s) - log(1-s)
* = 2s + 2/3 s**3 + 2/5 s**5 + .....,
* = 2s + s*R
* We use a special Remez algorithm on [0,0.1716] to generate
* a polynomial of degree 14 to approximate R The maximum error
* of this polynomial approximation is bounded by 2**-58.45. In
* other words,
* 2 4 6 8 10 12 14
* R(z) ~ Lg1*s +Lg2*s +Lg3*s +Lg4*s +Lg5*s +Lg6*s +Lg7*s
* (the values of Lg1 to Lg7 are listed in the program)
* and
* | 2 14 | -58.45
* | Lg1*s +...+Lg7*s - R(z) | <= 2
* | |
* Note that 2s = f - s*f = f - hfsq + s*hfsq, where hfsq = f*f/2.
* In order to guarantee error in log below 1ulp, we compute log
* by
* log(1+f) = f - s*(f - R) (if f is not too large)
* log(1+f) = f - (hfsq - s*(hfsq+R)). (better accuracy)
*
* 3. Finally, log(x) = k*ln2 + log(1+f).
* = k*ln2_hi+(f-(hfsq-(s*(hfsq+R)+k*ln2_lo)))
* Here ln2 is split into two floating point number:
* ln2_hi + ln2_lo,
* where n*ln2_hi is always exact for |n| < 2000.
*
* Special cases:
* log(x) is NaN with signal if x < 0 (including -INF) ;
* log(+INF) is +INF; log(0) is -INF with signal;
* log(NaN) is that NaN with no signal.
*
* Accuracy:
* according to an error analysis, the error is always less than
* 1 ulp (unit in the last place).
*
* Constants:
* The hexadecimal values are the intended ones for the following
* constants. The decimal values may be used, provided that the
* compiler will convert from decimal to binary accurately enough
* to produce the hexadecimal values shown.
*/
#[allow(clippy::eq_op, clippy::excessive_precision)]
#[cfg(all(not(feature = "std"), feature = "floats"))]
fn logd(mut x: f64) -> f64 {
const LN2_HI: f64 = 6.93147180369123816490e-01; /* 3fe62e42 fee00000 */
const LN2_LO: f64 = 1.90821492927058770002e-10; /* 3dea39ef 35793c76 */
const LG1: f64 = 6.666666666666735130e-01; /* 3FE55555 55555593 */
const LG2: f64 = 3.999999999940941908e-01; /* 3FD99999 9997FA04 */
const LG3: f64 = 2.857142874366239149e-01; /* 3FD24924 94229359 */
const LG4: f64 = 2.222219843214978396e-01; /* 3FCC71C5 1D8E78AF */
const LG5: f64 = 1.818357216161805012e-01; /* 3FC74664 96CB03DE */
const LG6: f64 = 1.531383769920937332e-01; /* 3FC39A09 D078C69F */
const LG7: f64 = 1.479819860511658591e-01; /* 3FC2F112 DF3E5244 */
let x1p54 = f64::from_bits(0x4350000000000000); // 0x1p54 === 2 ^ 54
let mut ui = x.to_bits();
let mut hx: u32 = (ui >> 32) as u32;
let mut k: i32 = 0;
if (hx < 0x00100000) || ((hx >> 31) != 0) {
/* x < 2**-126 */
if ui << 1 == 0 {
return -1. / (x * x); /* log(+-0)=-inf */
}
if hx >> 31 != 0 {
return (x - x) / 0.0; /* log(-#) = NaN */
}
/* subnormal number, scale x up */
k -= 54;
x *= x1p54;
ui = x.to_bits();
hx = (ui >> 32) as u32;
} else if hx >= 0x7ff00000 {
return x;
} else if hx == 0x3ff00000 && ui << 32 == 0 {
return 0.;
}
/* reduce x into [sqrt(2)/2, sqrt(2)] */
hx += 0x3ff00000 - 0x3fe6a09e;
k += ((hx >> 20) as i32) - 0x3ff;
hx = (hx & 0x000fffff) + 0x3fe6a09e;
ui = ((hx as u64) << 32) | (ui & 0xffffffff);
x = f64::from_bits(ui);
let f: f64 = x - 1.0;
let hfsq: f64 = 0.5 * f * f;
let s: f64 = f / (2.0 + f);
let z: f64 = s * s;
let w: f64 = z * z;
let t1: f64 = w * (LG2 + w * (LG4 + w * LG6));
let t2: f64 = z * (LG1 + w * (LG3 + w * (LG5 + w * LG7)));
let r: f64 = t2 + t1;
let dk: f64 = k as f64;
s * (hfsq + r) + dk * LN2_LO - hfsq + f + dk * LN2_HI
}
/* origin: FreeBSD /usr/src/lib/msun/src/e_logf.c */
/*
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
*/
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#[allow(clippy::eq_op, clippy::excessive_precision)]
#[cfg(all(not(feature = "std"), feature = "floats"))]
fn logf(mut x: f32) -> f32 {
const LN2_HI: f32 = 6.9313812256e-01; /* 0x3f317180 */
const LN2_LO: f32 = 9.0580006145e-06; /* 0x3717f7d1 */
/* |(log(1+s)-log(1-s))/s - Lg(s)| < 2**-34.24 (~[-4.95e-11, 4.97e-11]). */
const LG1: f32 = 0.66666662693; /* 0xaaaaaa.0p-24*/
const LG2: f32 = 0.40000972152; /* 0xccce13.0p-25 */
const LG3: f32 = 0.28498786688; /* 0x91e9ee.0p-25 */
const LG4: f32 = 0.24279078841; /* 0xf89e26.0p-26 */
let x1p25 = f32::from_bits(0x4c000000); // 0x1p25f === 2 ^ 25
let mut ix = x.to_bits();
let mut k = 0i32;
if (ix < 0x00800000) || ((ix >> 31) != 0) {
/* x < 2**-126 */
if ix << 1 == 0 {
return -1. / (x * x); /* log(+-0)=-inf */
}
if (ix >> 31) != 0 {
return (x - x) / 0.; /* log(-#) = NaN */
}
/* subnormal number, scale up x */
k -= 25;
x *= x1p25;
ix = x.to_bits();
} else if ix >= 0x7f800000 {
return x;
} else if ix == 0x3f800000 {
return 0.;
}
/* reduce x into [sqrt(2)/2, sqrt(2)] */
ix += 0x3f800000 - 0x3f3504f3;
k += ((ix >> 23) as i32) - 0x7f;
ix = (ix & 0x007fffff) + 0x3f3504f3;
x = f32::from_bits(ix);
let f = x - 1.;
let s = f / (2. + f);
let z = s * s;
let w = z * z;
let t1 = w * (LG2 + w * LG4);
let t2 = z * (LG1 + w * LG3);
let r = t2 + t1;
let hfsq = 0.5 * f * f;
let dk = k as f32;
s * (hfsq + r) + dk * LN2_LO - hfsq + f + dk * LN2_HI
}