53 lines
1.3 KiB
Go
53 lines
1.3 KiB
Go
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// Copyright 2010 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 runtime
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func complex128div(n complex128, d complex128) complex128 {
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// Special cases as in C99.
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ninf := real(n) == posinf || real(n) == neginf ||
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imag(n) == posinf || imag(n) == neginf
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dinf := real(d) == posinf || real(d) == neginf ||
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imag(d) == posinf || imag(d) == neginf
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nnan := !ninf && (real(n) != real(n) || imag(n) != imag(n))
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dnan := !dinf && (real(d) != real(d) || imag(d) != imag(d))
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switch {
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case nnan || dnan:
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return complex(nan, nan)
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case ninf && !dinf:
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return complex(posinf, posinf)
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case !ninf && dinf:
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return complex(0, 0)
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case real(d) == 0 && imag(d) == 0:
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if real(n) == 0 && imag(n) == 0 {
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return complex(nan, nan)
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} else {
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return complex(posinf, posinf)
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}
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default:
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// Standard complex arithmetic, factored to avoid unnecessary overflow.
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a := real(d)
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if a < 0 {
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a = -a
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}
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b := imag(d)
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if b < 0 {
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b = -b
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}
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if a <= b {
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ratio := real(d) / imag(d)
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denom := real(d)*ratio + imag(d)
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return complex((real(n)*ratio+imag(n))/denom,
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(imag(n)*ratio-real(n))/denom)
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} else {
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ratio := imag(d) / real(d)
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denom := imag(d)*ratio + real(d)
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return complex((imag(n)*ratio+real(n))/denom,
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(imag(n)-real(n)*ratio)/denom)
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}
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}
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}
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