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41 lines
617 B
Go
41 lines
617 B
Go
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// 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 atan2
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import atan "atan"
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export atan2
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/*
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atan2 discovers what quadrant the angle
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is in and calls atan.
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*/
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const
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(
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pio2 = .15707963267948966192313216e1;
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pi = .3141592653589793238462643383276e1;
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)
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func
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atan2(arg1, arg2 double) double
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{
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var x double;
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if arg1+arg2 == arg1 {
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if arg1 >= 0 {
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return pio2;
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}
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return -pio2;
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}
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x = atan.atan(arg1/arg2);
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if arg2 < 0 {
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if x <= 0 {
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return x + pi;
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}
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return x - pi;
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}
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return x;
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}
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