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 32-bits floats (`f32` type)
13 // FIXME: MIN_VALUE and MAX_VALUE literals are parsed as -inf and inf #14353
14 #![allow(overflowing_literals)]
16 #![stable(feature = "rust1", since = "1.0.0")]
22 use num
::{Float, ParseFloatError}
;
23 use num
::FpCategory
as Fp
;
25 #[stable(feature = "rust1", since = "1.0.0")]
26 #[allow(missing_docs)]
27 pub const RADIX
: u32 = 2;
29 #[stable(feature = "rust1", since = "1.0.0")]
30 #[allow(missing_docs)]
31 pub const MANTISSA_DIGITS
: u32 = 24;
32 #[stable(feature = "rust1", since = "1.0.0")]
33 #[allow(missing_docs)]
34 pub const DIGITS
: u32 = 6;
36 #[stable(feature = "rust1", since = "1.0.0")]
37 #[allow(missing_docs)]
38 pub const EPSILON
: f32 = 1.19209290e-07_f32;
40 /// Smallest finite f32 value
41 #[stable(feature = "rust1", since = "1.0.0")]
42 pub const MIN
: f32 = -3.40282347e+38_f32;
43 /// Smallest positive, normalized f32 value
44 #[stable(feature = "rust1", since = "1.0.0")]
45 pub const MIN_POSITIVE
: f32 = 1.17549435e-38_f32;
46 /// Largest finite f32 value
47 #[stable(feature = "rust1", since = "1.0.0")]
48 pub const MAX
: f32 = 3.40282347e+38_f32;
50 #[stable(feature = "rust1", since = "1.0.0")]
51 #[allow(missing_docs)]
52 pub const MIN_EXP
: i32 = -125;
53 #[stable(feature = "rust1", since = "1.0.0")]
54 #[allow(missing_docs)]
55 pub const MAX_EXP
: i32 = 128;
57 #[stable(feature = "rust1", since = "1.0.0")]
58 #[allow(missing_docs)]
59 pub const MIN_10_EXP
: i32 = -37;
60 #[stable(feature = "rust1", since = "1.0.0")]
61 #[allow(missing_docs)]
62 pub const MAX_10_EXP
: i32 = 38;
64 #[stable(feature = "rust1", since = "1.0.0")]
65 #[allow(missing_docs)]
66 pub const NAN
: f32 = 0.0_f32/0.0_f32;
67 #[stable(feature = "rust1", since = "1.0.0")]
68 #[allow(missing_docs)]
69 pub const INFINITY
: f32 = 1.0_f32/0.0_f32;
70 #[stable(feature = "rust1", since = "1.0.0")]
71 #[allow(missing_docs)]
72 pub const NEG_INFINITY
: f32 = -1.0_f32/0.0_f32;
74 /// Basic mathematical constants.
75 #[stable(feature = "rust1", since = "1.0.0")]
77 // FIXME: replace with mathematical constants from cmath.
79 /// Archimedes' constant
80 #[stable(feature = "rust1", since = "1.0.0")]
81 pub const PI
: f32 = 3.14159265358979323846264338327950288_f32;
84 #[stable(feature = "rust1", since = "1.0.0")]
85 pub const FRAC_PI_2
: f32 = 1.57079632679489661923132169163975144_f32;
88 #[stable(feature = "rust1", since = "1.0.0")]
89 pub const FRAC_PI_3
: f32 = 1.04719755119659774615421446109316763_f32;
92 #[stable(feature = "rust1", since = "1.0.0")]
93 pub const FRAC_PI_4
: f32 = 0.785398163397448309615660845819875721_f32;
96 #[stable(feature = "rust1", since = "1.0.0")]
97 pub const FRAC_PI_6
: f32 = 0.52359877559829887307710723054658381_f32;
100 #[stable(feature = "rust1", since = "1.0.0")]
101 pub const FRAC_PI_8
: f32 = 0.39269908169872415480783042290993786_f32;
104 #[stable(feature = "rust1", since = "1.0.0")]
105 pub const FRAC_1_PI
: f32 = 0.318309886183790671537767526745028724_f32;
108 #[stable(feature = "rust1", since = "1.0.0")]
109 pub const FRAC_2_PI
: f32 = 0.636619772367581343075535053490057448_f32;
112 #[stable(feature = "rust1", since = "1.0.0")]
113 pub const FRAC_2_SQRT_PI
: f32 = 1.12837916709551257389615890312154517_f32;
116 #[stable(feature = "rust1", since = "1.0.0")]
117 pub const SQRT_2
: f32 = 1.41421356237309504880168872420969808_f32;
120 #[stable(feature = "rust1", since = "1.0.0")]
121 pub const FRAC_1_SQRT_2
: f32 = 0.707106781186547524400844362104849039_f32;
124 #[stable(feature = "rust1", since = "1.0.0")]
125 pub const E
: f32 = 2.71828182845904523536028747135266250_f32;
128 #[stable(feature = "rust1", since = "1.0.0")]
129 pub const LOG2_E
: f32 = 1.44269504088896340735992468100189214_f32;
132 #[stable(feature = "rust1", since = "1.0.0")]
133 pub const LOG10_E
: f32 = 0.434294481903251827651128918916605082_f32;
136 #[stable(feature = "rust1", since = "1.0.0")]
137 pub const LN_2
: f32 = 0.693147180559945309417232121458176568_f32;
140 #[stable(feature = "rust1", since = "1.0.0")]
141 pub const LN_10
: f32 = 2.30258509299404568401799145468436421_f32;
144 #[unstable(feature = "core_float",
145 reason
= "stable interface is via `impl f{32,64}` in later crates",
149 fn nan() -> f32 { NAN }
152 fn infinity() -> f32 { INFINITY }
155 fn neg_infinity() -> f32 { NEG_INFINITY }
158 fn zero() -> f32 { 0.0 }
161 fn neg_zero() -> f32 { -0.0 }
164 fn one() -> f32 { 1.0 }
166 from_str_radix_float_impl
! { f32 }
168 /// Returns `true` if the number is NaN.
170 fn is_nan(self) -> bool { self != self }
172 /// Returns `true` if the number is infinite.
174 fn is_infinite(self) -> bool
{
175 self == Float
::infinity() || self == Float
::neg_infinity()
178 /// Returns `true` if the number is neither infinite or NaN.
180 fn is_finite(self) -> bool
{
181 !(self.is_nan() || self.is_infinite())
184 /// Returns `true` if the number is neither zero, infinite, subnormal or NaN.
186 fn is_normal(self) -> bool
{
187 self.classify() == Fp
::Normal
190 /// Returns the floating point category of the number. If only one property
191 /// is going to be tested, it is generally faster to use the specific
192 /// predicate instead.
193 fn classify(self) -> Fp
{
194 const EXP_MASK
: u32 = 0x7f800000;
195 const MAN_MASK
: u32 = 0x007fffff;
197 let bits
: u32 = unsafe { mem::transmute(self) }
;
198 match (bits
& MAN_MASK
, bits
& EXP_MASK
) {
200 (_
, 0) => Fp
::Subnormal
,
201 (0, EXP_MASK
) => Fp
::Infinite
,
202 (_
, EXP_MASK
) => Fp
::Nan
,
207 /// Returns the mantissa, exponent and sign as integers.
208 fn integer_decode(self) -> (u64, i16, i8) {
209 let bits
: u32 = unsafe { mem::transmute(self) }
;
210 let sign
: i8 = if bits
>> 31 == 0 { 1 }
else { -1 }
;
211 let mut exponent
: i16 = ((bits
>> 23) & 0xff) as i16;
212 let mantissa
= if exponent
== 0 {
213 (bits
& 0x7fffff) << 1
215 (bits
& 0x7fffff) | 0x800000
217 // Exponent bias + mantissa shift
218 exponent
-= 127 + 23;
219 (mantissa
as u64, exponent
, sign
)
222 /// Computes the absolute value of `self`. Returns `Float::nan()` if the
223 /// number is `Float::nan()`.
225 fn abs(self) -> f32 {
226 unsafe { intrinsics::fabsf32(self) }
229 /// Returns a number that represents the sign of `self`.
231 /// - `1.0` if the number is positive, `+0.0` or `Float::infinity()`
232 /// - `-1.0` if the number is negative, `-0.0` or `Float::neg_infinity()`
233 /// - `Float::nan()` if the number is `Float::nan()`
235 fn signum(self) -> f32 {
239 unsafe { intrinsics::copysignf32(1.0, self) }
243 /// Returns `true` if `self` is positive, including `+0.0` and
244 /// `Float::infinity()`.
246 fn is_sign_positive(self) -> bool
{
247 self > 0.0 || (1.0 / self) == Float
::infinity()
250 /// Returns `true` if `self` is negative, including `-0.0` and
251 /// `Float::neg_infinity()`.
253 fn is_sign_negative(self) -> bool
{
254 self < 0.0 || (1.0 / self) == Float
::neg_infinity()
257 /// Returns the reciprocal (multiplicative inverse) of the number.
259 fn recip(self) -> f32 { 1.0 / self }
262 fn powi(self, n
: i32) -> f32 {
263 unsafe { intrinsics::powif32(self, n) }
266 /// Converts to degrees, assuming the number is in radians.
268 fn to_degrees(self) -> f32 { self * (180.0f32 / consts::PI) }
270 /// Converts to radians, assuming the number is in degrees.
272 fn to_radians(self) -> f32 {
273 let value
: f32 = consts
::PI
;
274 self * (value
/ 180.0f32)