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f379ea0b07
move test.go to alll_test.go. R=r DELTA=1024 (521 added, 425 deleted, 78 changed) OCL=19687 CL=19695
68 lines
1.3 KiB
Go
68 lines
1.3 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package math
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/*
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Coefficients are #3370 from Hart & Cheney (18.80D).
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*/
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const
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(
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p0 = .1357884097877375669092680e8;
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p1 = -.4942908100902844161158627e7;
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p2 = .4401030535375266501944918e6;
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p3 = -.1384727249982452873054457e5;
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p4 = .1459688406665768722226959e3;
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q0 = .8644558652922534429915149e7;
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q1 = .4081792252343299749395779e6;
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q2 = .9463096101538208180571257e4;
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q3 = .1326534908786136358911494e3;
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piu2 = .6366197723675813430755350e0; // 2/pi
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)
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func Sinus(arg float64, quad int) float64 {
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x := arg;
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if(x < 0) {
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x = -x;
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quad = quad+2;
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}
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x = x * piu2; /* underflow? */
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var y float64;
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if x > 32764 {
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var e float64;
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e, y = sys.modf(x);
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e = e + float64(quad);
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temp1, f := sys.modf(0.25*e);
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quad = int(e - 4*f);
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} else {
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k := int32(x);
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y = x - float64(k);
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quad = (quad + int(k)) & 3;
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}
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if quad&1 != 0 {
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y = 1-y;
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}
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if quad > 1 {
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y = -y;
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}
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ysq := y*y;
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temp1 := ((((p4*ysq+p3)*ysq+p2)*ysq+p1)*ysq+p0)*y;
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temp2 := ((((ysq+q3)*ysq+q2)*ysq+q1)*ysq+q0);
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return temp1/temp2;
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}
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export func Cos(arg float64) float64 {
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if arg < 0 {
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arg = -arg;
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}
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return Sinus(arg, 1);
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}
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export func Sin(arg float64) float64 {
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return Sinus(arg, 0);
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}
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