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redo and clean up math.

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R=r
DELTA=243  (60 added, 72 deleted, 111 changed)
OCL=22909
CL=22912
This commit is contained in:
Russ Cox 2009-01-15 19:11:32 -08:00
parent 293c8f8c65
commit 2c8d9a5619
12 changed files with 170 additions and 182 deletions
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43
src/lib/math/sin.go
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@ -4,37 +4,34 @@
package math
/*
Coefficients are #3370 from Hart & Cheney (18.80D).
*/
const
(
sp0 = .1357884097877375669092680e8;
sp1 = -.4942908100902844161158627e7;
sp2 = .4401030535375266501944918e6;
sp3 = -.1384727249982452873054457e5;
sp4 = .1459688406665768722226959e3;
sq0 = .8644558652922534429915149e7;
sq1 = .4081792252343299749395779e6;
sq2 = .9463096101538208180571257e4;
sq3 = .1326534908786136358911494e3;
spiu2 = .6366197723675813430755350e0; // 2/pi
)
import "math"
func sinus(arg float64, quad int) float64 {
// Coefficients are #3370 from Hart & Cheney (18.80D).
const
(
P0 = .1357884097877375669092680e8;
P1 = -.4942908100902844161158627e7;
P2 = .4401030535375266501944918e6;
P3 = -.1384727249982452873054457e5;
P4 = .1459688406665768722226959e3;
Q0 = .8644558652922534429915149e7;
Q1 = .4081792252343299749395779e6;
Q2 = .9463096101538208180571257e4;
Q3 = .1326534908786136358911494e3;
)
x := arg;
if(x < 0) {
x = -x;
quad = quad+2;
}
x = x * spiu2; /* underflow? */
x = x * (2/Pi); /* underflow? */
var y float64;
if x > 32764 {
var e float64;
e, y = sys.modf(x);
e = e + float64(quad);
temsp1, f := sys.modf(0.25*e);
temp1, f := sys.modf(0.25*e);
quad = int(e - 4*f);
} else {
k := int32(x);
@ -49,10 +46,10 @@ func sinus(arg float64, quad int) float64 {
y = -y;
}
ysq := y*y;
temsp1 := ((((sp4*ysq+sp3)*ysq+sp2)*ysq+sp1)*ysq+sp0)*y;
temsp2 := ((((ysq+sq3)*ysq+sq2)*ysq+sq1)*ysq+sq0);
return temsp1/temsp2;
yy := y*y;
temp1 := ((((P4*yy+P3)*yy+P2)*yy+P1)*yy+P0)*y;
temp2 := ((((yy+Q3)*yy+Q2)*yy+Q1)*yy+Q0);
return temp1/temp2;
}
export func Cos(arg float64) float64 {