Files
addr2line
adler
adler32
ahash
aho_corasick
angle
approx
backtrace
bitflags
blender
bytemuck
byteorder
case
cast_trait
cfg_if
chrono
color
color_quant
const_fn
crc32fast
crossbeam
crossbeam_channel
crossbeam_deque
crossbeam_epoch
crossbeam_queue
crossbeam_skiplist
crossbeam_utils
darling
darling_core
darling_macro
dds
deflate
densevec
derive_builder
derive_builder_core
dot
downcast_rs
dual_quat
either
erased_serde
failure
failure_derive
fixedbitset
float_cmp
fnv
freeimage
freeimage_sys
freetype
freetype_gl_sys
freetype_sys
freetypegl
futures
futures_channel
futures_core
futures_executor
futures_io
futures_macro
futures_sink
futures_task
futures_util
async_await
future
io
lock
sink
stream
task
fxhash
generational_arena
generic_array
getrandom
gif
gimli
glfw
glfw_sys
glin
glin_derive
glsl
half
harfbuzz
harfbuzz_ft_sys
harfbuzz_sys
hashbrown
human_sort
ident_case
image
indexmap
instant
itertools
itoa
jpeg_decoder
lazy_static
libc
libm
lock_api
log
lut_parser
matrixmultiply
memchr
memoffset
meshopt
miniz_oxide
monotonic_clock
mopa
mutiny_derive
na
nalgebra
base
geometry
linalg
ncollide3d
bounding_volume
interpolation
partitioning
pipeline
procedural
query
algorithms
closest_points
contact
distance
nonlinear_time_of_impact
point
proximity
ray
time_of_impact
visitors
shape
transformation
utils
nom
num_complex
num_cpus
num_integer
num_iter
num_rational
num_traits
numext_constructor
numext_fixed_uint
numext_fixed_uint_core
numext_fixed_uint_hack
object
once_cell
parking_lot
parking_lot_core
pathfinding
pennereq
petgraph
pin_project_lite
pin_utils
png
polygon2
ppv_lite86
proc_macro2
proc_macro_crate
proc_macro_hack
proc_macro_nested
quote
rand
rand_chacha
rand_core
rand_distr
raw_window_handle
rawpointer
rayon
rayon_core
rect_packer
regex
regex_syntax
retain_mut
rin
rin_app
rin_blender
rin_core
rin_gl
rin_graphics
rin_gui
rin_material
rin_math
rin_postpo
rin_scene
rin_util
rin_window
rinblender
rinecs
rinecs_derive
rinecs_derive_utils
ringui_derive
rustc_demangle
rusty_pool
ryu
scopeguard
seitan
seitan_derive
semver
semver_parser
serde
serde_derive
serde_json
shaderdata_derive
simba
slab
slice_of_array
slotmap
smallvec
std140_data
streaming_iterator
strsim
syn
synstructure
thiserror
thiserror_impl
thread_local
tiff
time
toml
typenum
unchecked_unwrap
unicode_xid
vec2
vec3
weezl
x11
zlib_sys
 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
/* origin: FreeBSD /usr/src/lib/msun/src/s_log1pf.c */
/*
 * ====================================================
 * 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.
 * ====================================================
 */

use core::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 */

#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
pub fn log1pf(x: f32) -> f32 {
    let mut ui: u32 = x.to_bits();
    let hfsq: f32;
    let mut f: f32 = 0.;
    let mut c: f32 = 0.;
    let s: f32;
    let z: f32;
    let r: f32;
    let w: f32;
    let t1: f32;
    let t2: f32;
    let dk: f32;
    let ix: u32;
    let mut iu: u32;
    let mut k: i32;

    ix = ui;
    k = 1;
    if ix < 0x3ed413d0 || (ix >> 31) > 0 {
        /* 1+x < sqrt(2)+  */
        if ix >= 0xbf800000 {
            /* x <= -1.0 */
            if x == -1. {
                return x / 0.0; /* log1p(-1)=+inf */
            }
            return (x - x) / 0.0; /* log1p(x<-1)=NaN */
        }
        if ix << 1 < 0x33800000 << 1 {
            /* |x| < 2**-24 */
            /* underflow if subnormal */
            if (ix & 0x7f800000) == 0 {
                force_eval!(x * x);
            }
            return x;
        }
        if ix <= 0xbe95f619 {
            /* sqrt(2)/2- <= 1+x < sqrt(2)+ */
            k = 0;
            c = 0.;
            f = x;
        }
    } else if ix >= 0x7f800000 {
        return x;
    }
    if k > 0 {
        ui = (1. + x).to_bits();
        iu = ui;
        iu += 0x3f800000 - 0x3f3504f3;
        k = (iu >> 23) as i32 - 0x7f;
        /* correction term ~ log(1+x)-log(u), avoid underflow in c/u */
        if k < 25 {
            c = if k >= 2 {
                1. - (f32::from_bits(ui) - x)
            } else {
                x - (f32::from_bits(ui) - 1.)
            };
            c /= f32::from_bits(ui);
        } else {
            c = 0.;
        }
        /* reduce u into [sqrt(2)/2, sqrt(2)] */
        iu = (iu & 0x007fffff) + 0x3f3504f3;
        ui = iu;
        f = f32::from_bits(ui) - 1.;
    }
    s = f / (2.0 + f);
    z = s * s;
    w = z * z;
    t1 = w * (LG2 + w * LG4);
    t2 = z * (LG1 + w * LG3);
    r = t2 + t1;
    hfsq = 0.5 * f * f;
    dk = k as f32;
    s * (hfsq + r) + (dk * LN2_LO + c) - hfsq + f + dk * LN2_HI
}