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60 lines
868 B
Go
60 lines
868 B
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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import math "atan"
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import math "sqrt"
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export asin, acos
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/*
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* asin(arg) and acos(arg) return the arcsin, arccos,
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* respectively of their arguments.
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*
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* Arctan is called after appropriate range reduction.
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*/
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const
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(
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pio2 = .15707963267948966192313216e1;
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)
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func
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asin(arg double)double
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{
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var temp, x double;
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var sign bool;
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sign = false;
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x = arg;
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if x < 0 {
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x = -x;
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sign = true;
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}
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if arg > 1 {
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return sys.NaN();
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}
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temp = sqrt(1 - x*x);
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if x > 0.7 {
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temp = pio2 - atan(temp/x);
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} else {
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temp = atan(x/temp);
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}
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if sign {
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temp = -temp;
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}
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return temp;
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}
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func
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acos(arg double)double
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{
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if(arg > 1 || arg < -1) {
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return sys.NaN();
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}
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return pio2 - asin(arg);
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}
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