1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Operations and constants for 64-bits floats (`f64` type)
13 #![doc(primitive = "f64")]
14 // FIXME: MIN_VALUE and MAX_VALUE literals are parsed as -inf and inf #14353
15 #![allow(overflowing_literals)]
22 use num::FpCategory as Fp;
25 // FIXME(#5527): These constants should be deprecated once associated
26 // constants are implemented in favour of referencing the respective
27 // members of `Bounded` and `Float`.
30 pub const RADIX: uint = 2u;
33 pub const MANTISSA_DIGITS: uint = 53u;
35 pub const DIGITS: uint = 15u;
38 pub const EPSILON: f64 = 2.2204460492503131e-16_f64;
40 /// Smallest finite f64 value
42 pub const MIN_VALUE: f64 = -1.7976931348623157e+308_f64;
43 /// Smallest positive, normalized f64 value
45 pub const MIN_POS_VALUE: f64 = 2.2250738585072014e-308_f64;
46 /// Largest finite f64 value
48 pub const MAX_VALUE: f64 = 1.7976931348623157e+308_f64;
51 pub const MIN_EXP: int = -1021;
53 pub const MAX_EXP: int = 1024;
56 pub const MIN_10_EXP: int = -307;
58 pub const MAX_10_EXP: int = 308;
61 pub const NAN: f64 = 0.0_f64/0.0_f64;
63 pub const INFINITY: f64 = 1.0_f64/0.0_f64;
65 pub const NEG_INFINITY: f64 = -1.0_f64/0.0_f64;
67 /// Various useful constants.
68 #[unstable = "naming scheme needs to be revisited"]
70 // FIXME: replace with mathematical constants from cmath.
72 // FIXME(#5527): These constants should be deprecated once associated
73 // constants are implemented in favour of referencing the respective members
76 /// Archimedes' constant
77 pub const PI: f64 = 3.14159265358979323846264338327950288_f64;
80 pub const PI_2: f64 = 6.28318530717958647692528676655900576_f64;
83 pub const FRAC_PI_2: f64 = 1.57079632679489661923132169163975144_f64;
86 pub const FRAC_PI_3: f64 = 1.04719755119659774615421446109316763_f64;
89 pub const FRAC_PI_4: f64 = 0.785398163397448309615660845819875721_f64;
92 pub const FRAC_PI_6: f64 = 0.52359877559829887307710723054658381_f64;
95 pub const FRAC_PI_8: f64 = 0.39269908169872415480783042290993786_f64;
98 pub const FRAC_1_PI: f64 = 0.318309886183790671537767526745028724_f64;
101 pub const FRAC_2_PI: f64 = 0.636619772367581343075535053490057448_f64;
104 pub const FRAC_2_SQRTPI: f64 = 1.12837916709551257389615890312154517_f64;
107 pub const SQRT2: f64 = 1.41421356237309504880168872420969808_f64;
110 pub const FRAC_1_SQRT2: f64 = 0.707106781186547524400844362104849039_f64;
113 pub const E: f64 = 2.71828182845904523536028747135266250_f64;
116 pub const LOG2_E: f64 = 1.44269504088896340735992468100189214_f64;
119 pub const LOG10_E: f64 = 0.434294481903251827651128918916605082_f64;
122 pub const LN_2: f64 = 0.693147180559945309417232121458176568_f64;
125 pub const LN_10: f64 = 2.30258509299404568401799145468436421_f64;
128 #[unstable = "trait is unstable"]
131 fn nan() -> f64 { NAN }
134 fn infinity() -> f64 { INFINITY }
137 fn neg_infinity() -> f64 { NEG_INFINITY }
140 fn zero() -> f64 { 0.0 }
143 fn neg_zero() -> f64 { -0.0 }
146 fn one() -> f64 { 1.0 }
148 /// Returns `true` if the number is NaN.
150 fn is_nan(self) -> bool { self != self }
152 /// Returns `true` if the number is infinite.
154 fn is_infinite(self) -> bool {
155 self == Float::infinity() || self == Float::neg_infinity()
158 /// Returns `true` if the number is neither infinite or NaN.
160 fn is_finite(self) -> bool {
161 !(self.is_nan() || self.is_infinite())
164 /// Returns `true` if the number is neither zero, infinite, subnormal or NaN.
166 fn is_normal(self) -> bool {
167 self.classify() == Fp::Normal
170 /// Returns the floating point category of the number. If only one property
171 /// is going to be tested, it is generally faster to use the specific
172 /// predicate instead.
173 fn classify(self) -> Fp {
174 const EXP_MASK: u64 = 0x7ff0000000000000;
175 const MAN_MASK: u64 = 0x000fffffffffffff;
177 let bits: u64 = unsafe { mem::transmute(self) };
178 match (bits & MAN_MASK, bits & EXP_MASK) {
180 (_, 0) => Fp::Subnormal,
181 (0, EXP_MASK) => Fp::Infinite,
182 (_, EXP_MASK) => Fp::Nan,
188 fn mantissa_digits(_: Option<f64>) -> uint { MANTISSA_DIGITS }
191 fn digits(_: Option<f64>) -> uint { DIGITS }
194 fn epsilon() -> f64 { EPSILON }
197 fn min_exp(_: Option<f64>) -> int { MIN_EXP }
200 fn max_exp(_: Option<f64>) -> int { MAX_EXP }
203 fn min_10_exp(_: Option<f64>) -> int { MIN_10_EXP }
206 fn max_10_exp(_: Option<f64>) -> int { MAX_10_EXP }
209 fn min_value() -> f64 { MIN_VALUE }
212 fn min_pos_value(_: Option<f64>) -> f64 { MIN_POS_VALUE }
215 fn max_value() -> f64 { MAX_VALUE }
217 /// Returns the mantissa, exponent and sign as integers.
218 fn integer_decode(self) -> (u64, i16, i8) {
219 let bits: u64 = unsafe { mem::transmute(self) };
220 let sign: i8 = if bits >> 63 == 0 { 1 } else { -1 };
221 let mut exponent: i16 = ((bits >> 52) & 0x7ff) as i16;
222 let mantissa = if exponent == 0 {
223 (bits & 0xfffffffffffff) << 1
225 (bits & 0xfffffffffffff) | 0x10000000000000
227 // Exponent bias + mantissa shift
228 exponent -= 1023 + 52;
229 (mantissa, exponent, sign)
232 /// Rounds towards minus infinity.
234 fn floor(self) -> f64 {
235 unsafe { intrinsics::floorf64(self) }
238 /// Rounds towards plus infinity.
240 fn ceil(self) -> f64 {
241 unsafe { intrinsics::ceilf64(self) }
244 /// Rounds to nearest integer. Rounds half-way cases away from zero.
246 fn round(self) -> f64 {
247 unsafe { intrinsics::roundf64(self) }
250 /// Returns the integer part of the number (rounds towards zero).
252 fn trunc(self) -> f64 {
253 unsafe { intrinsics::truncf64(self) }
256 /// The fractional part of the number, satisfying:
259 /// use core::num::Float;
262 /// assert!(x == x.trunc() + x.fract())
265 fn fract(self) -> f64 { self - self.trunc() }
267 /// Computes the absolute value of `self`. Returns `Float::nan()` if the
268 /// number is `Float::nan()`.
270 fn abs(self) -> f64 {
271 unsafe { intrinsics::fabsf64(self) }
274 /// Returns a number that represents the sign of `self`.
276 /// - `1.0` if the number is positive, `+0.0` or `Float::infinity()`
277 /// - `-1.0` if the number is negative, `-0.0` or `Float::neg_infinity()`
278 /// - `Float::nan()` if the number is `Float::nan()`
280 fn signum(self) -> f64 {
284 unsafe { intrinsics::copysignf64(1.0, self) }
288 /// Returns `true` if `self` is positive, including `+0.0` and
289 /// `Float::infinity()`.
291 fn is_positive(self) -> bool {
292 self > 0.0 || (1.0 / self) == Float::infinity()
295 /// Returns `true` if `self` is negative, including `-0.0` and
296 /// `Float::neg_infinity()`.
298 fn is_negative(self) -> bool {
299 self < 0.0 || (1.0 / self) == Float::neg_infinity()
302 /// Fused multiply-add. Computes `(self * a) + b` with only one rounding
303 /// error. This produces a more accurate result with better performance than
304 /// a separate multiplication operation followed by an add.
306 fn mul_add(self, a: f64, b: f64) -> f64 {
307 unsafe { intrinsics::fmaf64(self, a, b) }
310 /// Returns the reciprocal (multiplicative inverse) of the number.
312 fn recip(self) -> f64 { 1.0 / self }
315 fn powf(self, n: f64) -> f64 {
316 unsafe { intrinsics::powf64(self, n) }
320 fn powi(self, n: i32) -> f64 {
321 unsafe { intrinsics::powif64(self, n) }
325 fn sqrt(self) -> f64 {
329 unsafe { intrinsics::sqrtf64(self) }
334 fn rsqrt(self) -> f64 { self.sqrt().recip() }
336 /// Returns the exponential of the number.
338 fn exp(self) -> f64 {
339 unsafe { intrinsics::expf64(self) }
342 /// Returns 2 raised to the power of the number.
344 fn exp2(self) -> f64 {
345 unsafe { intrinsics::exp2f64(self) }
348 /// Returns the natural logarithm of the number.
351 unsafe { intrinsics::logf64(self) }
354 /// Returns the logarithm of the number with respect to an arbitrary base.
356 fn log(self, base: f64) -> f64 { self.ln() / base.ln() }
358 /// Returns the base 2 logarithm of the number.
360 fn log2(self) -> f64 {
361 unsafe { intrinsics::log2f64(self) }
364 /// Returns the base 10 logarithm of the number.
366 fn log10(self) -> f64 {
367 unsafe { intrinsics::log10f64(self) }
370 /// Converts to degrees, assuming the number is in radians.
372 fn to_degrees(self) -> f64 { self * (180.0f64 / consts::PI) }
374 /// Converts to radians, assuming the number is in degrees.
376 fn to_radians(self) -> f64 {
377 let value: f64 = consts::PI;
378 self * (value / 180.0)