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
// origin: FreeBSD /usr/src/lib/msun/src/s_cos.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 super::{k_cos, k_sin, rem_pio2};

// cos(x)
// Return cosine function of x.
//
// kernel function:
//      k_sin           ... sine function on [-pi/4,pi/4]
//      k_cos           ... cosine function on [-pi/4,pi/4]
//      rem_pio2        ... argument reduction routine
//
// Method.
//      Let S,C and T denote the sin, cos and tan respectively on
//      [-PI/4, +PI/4]. Reduce the argument x to y1+y2 = x-k*pi/2
//      in [-pi/4 , +pi/4], and let n = k mod 4.
//      We have
//
//          n        sin(x)      cos(x)        tan(x)
//     ----------------------------------------------------------
//          0          S           C             T
//          1          C          -S            -1/T
//          2         -S          -C             T
//          3         -C           S            -1/T
//     ----------------------------------------------------------
//
// Special cases:
//      Let trig be any of sin, cos, or tan.
//      trig(+-INF)  is NaN, with signals;
//      trig(NaN)    is that NaN;
//
// Accuracy:
//      TRIG(x) returns trig(x) nearly rounded
//
#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
pub fn cos(x: f64) -> f64 {
    let ix = (f64::to_bits(x) >> 32) as u32 & 0x7fffffff;

    /* |x| ~< pi/4 */
    if ix <= 0x3fe921fb {
        if ix < 0x3e46a09e {
            /* if x < 2**-27 * sqrt(2) */
            /* raise inexact if x != 0 */
            if x as i32 == 0 {
                return 1.0;
            }
        }
        return k_cos(x, 0.0);
    }

    /* cos(Inf or NaN) is NaN */
    if ix >= 0x7ff00000 {
        return x - x;
    }

    /* argument reduction needed */
    let (n, y0, y1) = rem_pio2(x);
    match n & 3 {
        0 => k_cos(y0, y1),
        1 => -k_sin(y0, y1, 1),
        2 => -k_cos(y0, y1),
        _ => k_sin(y0, y1, 1),
    }
}